binbinyang-----自定义VIEW.刻度尺.左右滑动选择对应数值

 很多APP.如今会用到横向刻度尺,或是纵向刻度尺....比如在个人资料填入.或是减肥APP里面...随处可见

今天我带来一个 

先发,我录制的动态GIF效果图

放代码

主Activity

public class MainActivity extends AppCompatActivity implements  HorizontalPicker.OnItemSelected, HorizontalPicker.OnItemClicked {    HorizontalPicker pick;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        //数据类型(0 卡路里,100-2000, 1:步数 2000-20000 2;公里:1-20        //默认选中数        pick  =(HorizontalPicker)findViewById(R.id.picker);        pick.setDataType(2,"10");        pick.setOnItemClickedListener(this);        pick.setOnItemSelectedListener(this);    }    @Override    public void onItemClicked(int index) {        Toast.makeText(this, index+"", 1).show();    }    @Override    public void onItemSelected(String item) {        Toast.makeText(this, item, 1).show();    }}

xml布局

<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"              xmlns:app="http://schemas.android.com/apk/res-auto"              xmlns:tools="http://schemas.android.com/tools"              android:layout_width="match_parent"              android:layout_height="match_parent"              android:background="#FFFFFF"              android:orientation="vertical"               >    <com.example.yangbin.pickm.HorizontalPicker        android:id="@+id/picker"        android:layout_width="match_parent"        android:layout_height="80dp"        android:layout_marginTop="30dp"        android:background="#FFFFFF"        android:ellipsize="marquee"        android:focusable="true"        android:focusableInTouchMode="true"        android:marqueeRepeatLimit="2"        android:paddingBottom="16dp"        android:paddingTop="16dp"        android:textColor="#727272"        android:textSize="22sp"        app:dividerSize="0dp"        app:sideItems="2" />    <com.example.yangbin.pickm.MyScaleView        android:layout_width="wrap_content"        android:layout_height="15dp" /></LinearLayout>

自定义 

HorizontalPicker

/* * Copyright 2014 Blaž Šolar * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * *     http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */package com.example.yangbin.pickm;import android.animation.ArgbEvaluator;import android.annotation.TargetApi;import android.content.Context;import android.content.res.ColorStateList;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;import android.graphics.RectF;import android.os.Build;import android.os.Bundle;import android.os.Handler;import android.os.Message;import android.os.Parcel;import android.os.Parcelable;import android.support.v4.text.TextDirectionHeuristicCompat;import android.support.v4.text.TextDirectionHeuristicsCompat;import android.support.v4.view.ViewCompat;import android.support.v4.view.accessibility.AccessibilityNodeInfoCompat;import android.support.v4.widget.ExploreByTouchHelper;import android.text.BoringLayout;import android.text.Layout;import android.text.TextPaint;import android.text.TextUtils;import android.util.AttributeSet;import android.view.KeyEvent;import android.view.MotionEvent;import android.view.VelocityTracker;import android.view.View;import android.view.ViewConfiguration;import android.view.accessibility.AccessibilityEvent;import android.view.animation.DecelerateInterpolator;import android.widget.EdgeEffect;import android.widget.OverScroller;import java.lang.ref.WeakReference;import java.util.ArrayList;import java.util.List;/** * Created by Blaž Šolar on 24/01/14. */public class HorizontalPicker extends View {    public static final String TAG = "HorizontalTimePicker";    /**     * The coefficient by which to adjust (divide) the max fling velocity.     */    private static final int SELECTOR_MAX_FLING_VELOCITY_ADJUSTMENT = 4;    /**     * The the duration for adjusting the selector wheel.     */    private static final int SELECTOR_ADJUSTMENT_DURATION_MILLIS = 800;    /**     * Determines speed during touch scrolling.     */    private VelocityTracker mVelocityTracker;    /**     * @see ViewConfiguration#getScaledMinimumFlingVelocity()     */    private int mMinimumFlingVelocity;    /**     * @see ViewConfiguration#getScaledMaximumFlingVelocity()     */    private int maximumFlingVelocity;    private final int overscrollDistance;    private int touchSlop;    private CharSequence[] values;    private BoringLayout[] layouts;    private TextPaint textPaint;    private BoringLayout.Metrics boringMetrics;    private TextUtils.TruncateAt ellipsize;    private int itemWidth;    private RectF itemClipBounds;    private RectF itemClipBoundsOffset;    private float lastDownEventX;    private OverScroller flingScrollerX;    private OverScroller adjustScrollerX;    private int previousScrollerX;    private boolean scrollingX;    private int pressedItem = -1;    private ColorStateList textColor;    private OnItemSelected onItemSelected;    private OnItemClicked onItemClicked;    private int selectedItem;    private EdgeEffect leftEdgeEffect;    private EdgeEffect rightEdgeEffect;    private Marquee marquee;    private int marqueeRepeatLimit = 3;    private float dividerSize = 0;    private int sideItems = 1;    private TextDirectionHeuristicCompat textDir;    private final PickerTouchHelper touchHelper;    private Paint paint;    private int mWidth;    private int mHeight;    private String[] arrays;    private int mDataType = 0;    public void setDataType(int type, String value) {        mDataType = type;        setValues(getData(mDataType));        setSelectedItem(value);        invalidate();    }    public int getDataType() {        return mDataType;    }    private void init() {        paint = new Paint();        paint.setColor(Color.GRAY);        paint.setAntiAlias(true);        paint.setStrokeWidth(2);    }    public HorizontalPicker(Context context) {        this(context, null);    }    public HorizontalPicker(Context context, AttributeSet attrs) {        this(context, attrs, R.attr.horizontalPickerStyle);    }    public HorizontalPicker(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        init();        // create the selector wheel paint        TextPaint paint = new TextPaint();        paint.setAntiAlias(true);        textPaint = paint;        TypedArray a = context.getTheme().obtainStyledAttributes(                attrs,                R.styleable.HorizontalPicker,                defStyle, 0        );        int ellipsize = 3; // END default value        int sideItems = this.sideItems;        try {            textColor = a.getColorStateList(R.styleable.HorizontalPicker_android_textColor);            if (textColor == null) {                textColor = ColorStateList.valueOf(0xFF000000);            }            ellipsize = a.getInt(R.styleable.HorizontalPicker_android_ellipsize, ellipsize);            marqueeRepeatLimit = a.getInt(R.styleable.HorizontalPicker_android_marqueeRepeatLimit, marqueeRepeatLimit);            dividerSize = a.getDimension(R.styleable.HorizontalPicker_dividerSize, dividerSize);            sideItems = a.getInt(R.styleable.HorizontalPicker_sideItems, sideItems);            float textSize = a.getDimension(R.styleable.HorizontalPicker_android_textSize, -1);            if (textSize > -1) {                setTextSize(textSize);            }        } finally {            a.recycle();        }        switch (ellipsize) {            case 1:                setEllipsize(TextUtils.TruncateAt.START);                break;            case 2:                setEllipsize(TextUtils.TruncateAt.MIDDLE);                break;            case 3:                setEllipsize(TextUtils.TruncateAt.END);                break;            case 4:                setEllipsize(TextUtils.TruncateAt.MARQUEE);                break;        }        Paint.FontMetricsInt fontMetricsInt = textPaint.getFontMetricsInt();        boringMetrics = new BoringLayout.Metrics();        boringMetrics.ascent = fontMetricsInt.ascent;        boringMetrics.bottom = fontMetricsInt.bottom;        boringMetrics.descent = fontMetricsInt.descent;        boringMetrics.leading = fontMetricsInt.leading;        boringMetrics.top = fontMetricsInt.top;        boringMetrics.width = itemWidth;        setWillNotDraw(false);        flingScrollerX = new OverScroller(context);        adjustScrollerX = new OverScroller(context, new DecelerateInterpolator(2.5f));        // initialize constants        ViewConfiguration configuration = ViewConfiguration.get(context);        touchSlop = configuration.getScaledTouchSlop();        mMinimumFlingVelocity = configuration.getScaledMinimumFlingVelocity();        maximumFlingVelocity = configuration.getScaledMaximumFlingVelocity()                / SELECTOR_MAX_FLING_VELOCITY_ADJUSTMENT;        overscrollDistance = configuration.getScaledOverscrollDistance();        previousScrollerX = Integer.MIN_VALUE;        //********添加数据**********        setValues(getData(getDataType()));        setSideItems(sideItems);        touchHelper = new PickerTouchHelper(this);        ViewCompat.setAccessibilityDelegate(this, touchHelper);    }    /**     * 自定义数据     *     * @return     */    private String[] getData(int type) {        List<String> list = new ArrayList<>();        if (type == 1) {            arrays = new String[19];            for (int i = 2000; i <= 20000; i += 1000) {                list.add(i + "");            }            for (int k = 0; k < 19; k++) {                arrays[k] = list.get(k);            }        } else {            if (type == 0) {                arrays = new String[20];                for (int i = 100; i <= 2000; i += 100) {                    list.add(i + "");                }            } else if (type == 2) {                arrays = new String[20];                for (int i = 1; i <= 20; i += 1) {                    list.add(i + "");                }            }            for (int k = 0; k < 20; k++) {                arrays[k] = list.get(k);            }        }        return arrays;    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        int heightMode = MeasureSpec.getMode(heightMeasureSpec);        int width = MeasureSpec.getSize(widthMeasureSpec);        int heightSize = MeasureSpec.getSize(heightMeasureSpec);        int height;        if (heightMode == MeasureSpec.EXACTLY) {            height = heightSize;        } else {            Paint.FontMetrics fontMetrics = textPaint.getFontMetrics();            int heightText = (int) (Math.abs(fontMetrics.ascent) + Math.abs(fontMetrics.descent));            heightText += getPaddingTop() + getPaddingBottom();            if (heightMode == MeasureSpec.AT_MOST) {                height = Math.min(heightSize, heightText);            } else {                height = heightText;            }        }        setMeasuredDimension(width, height);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        mWidth = getWidth();        mHeight = getHeight();        int saveCount = canvas.getSaveCount();        canvas.save();        int selectedItem = this.selectedItem;        float itemWithPadding = itemWidth + dividerSize;        // translate horizontal to center        canvas.translate(itemWithPadding * sideItems, 0);        if (values != null) {            for (int i = 0; i < values.length; i++) {                // set text color for item                textPaint.setColor(getTextColor(i));                // get text layout                BoringLayout layout = layouts[i];                int saveCountHeight = canvas.getSaveCount();                canvas.save();                float x = 0;                float lineWidth = layout.getLineWidth(0);                if (lineWidth > itemWidth) {                    if (isRtl(values[i])) {                        x += (lineWidth - itemWidth) / 2;                    } else {                        x -= (lineWidth - itemWidth) / 2;                    }                }                if (marquee != null && i == selectedItem) {                    x += marquee.getScroll();                }                // translate vertically to center                canvas.translate(-x, (canvas.getHeight() - layout.getHeight()) / 2);                RectF clipBounds;                if (x == 0) {                    clipBounds = itemClipBounds;                } else {                    clipBounds = itemClipBoundsOffset;                    clipBounds.set(itemClipBounds);                    clipBounds.offset(x, 0);                }                canvas.clipRect(clipBounds);                layout.draw(canvas);                if (marquee != null && i == selectedItem && marquee.shouldDrawGhost()) {                    canvas.translate(marquee.getGhostOffset(), 0);                    layout.draw(canvas);                }                // restore vertical translation                canvas.restoreToCount(saveCountHeight);                // 画刻度线                paint.setColor(getTextColor(i));                canvas.drawLine(itemWidth / 2, mHeight - 20, itemWidth / 2, mHeight - 45, paint);                // translate horizontal for 1 item                canvas.translate(itemWithPadding, 0);            }        }        // restore horizontal translation        canvas.restoreToCount(saveCount);        drawEdgeEffect(canvas, leftEdgeEffect, 270);        drawEdgeEffect(canvas, rightEdgeEffect, 90);    }    @TargetApi(Build.VERSION_CODES.JELLY_BEAN_MR1)    @Override    public void onRtlPropertiesChanged(int layoutDirection) {        super.onRtlPropertiesChanged(layoutDirection);        textDir = getTextDirectionHeuristic();    }    /**     * TODO cache values     *     * @param text     * @return     */    private boolean isRtl(CharSequence text) {        if (textDir == null) {            textDir = getTextDirectionHeuristic();        }        return textDir.isRtl(text, 0, text.length());    }    private TextDirectionHeuristicCompat getTextDirectionHeuristic() {        if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN_MR1) {            return TextDirectionHeuristicsCompat.FIRSTSTRONG_LTR;        } else {            // Always need to resolve layout direction first            final boolean defaultIsRtl = (getLayoutDirection() == LAYOUT_DIRECTION_RTL);            switch (getTextDirection()) {                default:                case TEXT_DIRECTION_FIRST_STRONG:                    return (defaultIsRtl ? TextDirectionHeuristicsCompat.FIRSTSTRONG_RTL :                            TextDirectionHeuristicsCompat.FIRSTSTRONG_LTR);                case TEXT_DIRECTION_ANY_RTL:                    return TextDirectionHeuristicsCompat.ANYRTL_LTR;                case TEXT_DIRECTION_LTR:                    return TextDirectionHeuristicsCompat.LTR;                case TEXT_DIRECTION_RTL:                    return TextDirectionHeuristicsCompat.RTL;                case TEXT_DIRECTION_LOCALE:                    return TextDirectionHeuristicsCompat.LOCALE;            }        }    }    private void remakeLayout() {        if (layouts != null && layouts.length > 0 && getWidth() > 0) {            for (int i = 0; i < layouts.length; i++) {                layouts[i].replaceOrMake(values[i], textPaint, itemWidth,                        Layout.Alignment.ALIGN_CENTER, 1f, 1f, boringMetrics, false, ellipsize,                        itemWidth);            }        }    }    private void drawEdgeEffect(Canvas canvas, EdgeEffect edgeEffect, int degrees) {        if (canvas == null || edgeEffect == null || (degrees != 90 && degrees != 270)) {            return;        }        if (!edgeEffect.isFinished()) {            final int restoreCount = canvas.getSaveCount();            final int width = getWidth();            final int height = getHeight();            canvas.rotate(degrees);            if (degrees == 270) {                canvas.translate(-height, Math.max(0, getScrollX()));            } else { // 90                canvas.translate(0, -(Math.max(getScrollRange(), getScaleX()) + width));            }            edgeEffect.setSize(height, width);            if (edgeEffect.draw(canvas)) {                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {                    postInvalidateOnAnimation();                } else {                    postInvalidate();                }            }            canvas.restoreToCount(restoreCount);        }    }    /**     * Calculates text color for specified item based on its position and state.     *     * @param item Index of item to get text color for     * @return Item text color     */    private int getTextColor(int item) {        int scrollX = getScrollX();        // set color of text        int color = textColor.getDefaultColor();        int itemWithPadding = (int) (itemWidth + dividerSize);        if (scrollX > itemWithPadding * item - itemWithPadding / 2 &&                scrollX < itemWithPadding * (item + 1) - itemWithPadding / 2) {            int position = scrollX - itemWithPadding / 2;            color = getColor(position, item);        } else if (item == pressedItem) {            color = textColor.getColorForState(new int[]{android.R.attr.state_pressed}, color);        }        return color;    }    @Override    protected void onSizeChanged(int w, int h, int oldw, int oldh) {        super.onSizeChanged(w, h, oldw, oldh);        calculateItemSize(w, h);    }    @Override    public boolean onTouchEvent(MotionEvent event) {        if (!isEnabled()) {            return false;        }        if (mVelocityTracker == null) {            mVelocityTracker = VelocityTracker.obtain();        }        mVelocityTracker.addMovement(event);        int action = event.getActionMasked();        switch (action) {            case MotionEvent.ACTION_MOVE:                float currentMoveX = event.getX();                int deltaMoveX = (int) (lastDownEventX - currentMoveX);                if (scrollingX ||                        (Math.abs(deltaMoveX) > touchSlop) && values != null && values.length > 0) {                    if (!scrollingX) {                        deltaMoveX = 0;                        pressedItem = -1;                        scrollingX = true;                        getParent().requestDisallowInterceptTouchEvent(true);                        stopMarqueeIfNeeded();                    }                    final int range = getScrollRange();                    if (overScrollBy(deltaMoveX, 0, getScrollX(), 0, range, 0,                            overscrollDistance, 0, true)) {                        mVelocityTracker.clear();                    }                    final float pulledToX = getScrollX() + deltaMoveX;                    if (pulledToX < 0) {                        leftEdgeEffect.onPull((float) deltaMoveX / getWidth());                        if (!rightEdgeEffect.isFinished()) {                            rightEdgeEffect.onRelease();                        }                    } else if (pulledToX > range) {                        rightEdgeEffect.onPull((float) deltaMoveX / getWidth());                        if (!leftEdgeEffect.isFinished()) {                            leftEdgeEffect.onRelease();                        }                    }                    lastDownEventX = currentMoveX;                    invalidate();                }                break;            case MotionEvent.ACTION_DOWN:                if (!adjustScrollerX.isFinished()) {                    adjustScrollerX.forceFinished(true);                } else if (!flingScrollerX.isFinished()) {                    flingScrollerX.forceFinished(true);                } else {                    scrollingX = false;                }                lastDownEventX = event.getX();                if (!scrollingX) {                    pressedItem = getPositionFromTouch(event.getX());                }                invalidate();                break;            case MotionEvent.ACTION_UP:                VelocityTracker velocityTracker = mVelocityTracker;                velocityTracker.computeCurrentVelocity(1000, maximumFlingVelocity);                int initialVelocityX = (int) velocityTracker.getXVelocity();                if (scrollingX && Math.abs(initialVelocityX) > mMinimumFlingVelocity) {                    flingX(initialVelocityX);                } else if (values != null) {                    float positionX = event.getX();                    if (!scrollingX) {                        int itemPos = getPositionOnScreen(positionX);                        int relativePos = itemPos - sideItems;                        if (relativePos == 0) {                            selectItem();                        } else {                            smoothScrollBy(relativePos);                        }                    } else if (scrollingX) {                        finishScrolling();                    }                }                mVelocityTracker.recycle();                mVelocityTracker = null;                if (leftEdgeEffect != null) {                    leftEdgeEffect.onRelease();                    rightEdgeEffect.onRelease();                }            case MotionEvent.ACTION_CANCEL:                pressedItem = -1;                invalidate();                if (leftEdgeEffect != null) {                    leftEdgeEffect.onRelease();                    rightEdgeEffect.onRelease();                }                break;        }        return true;    }    private void selectItem() {        // post to the UI Thread to avoid potential interference with the OpenGL Thread        if (onItemClicked != null) {            post(new Runnable() {                @Override                public void run() {                    onItemClicked.onItemClicked(getSelectedItem());                }            });        }        adjustToNearestItemX();    }    @Override    public boolean onKeyDown(int keyCode, KeyEvent event) {        if (!isEnabled()) {            return super.onKeyDown(keyCode, event);        }        switch (keyCode) {            case KeyEvent.KEYCODE_DPAD_CENTER:            case KeyEvent.KEYCODE_ENTER:                selectItem();                return true;            case KeyEvent.KEYCODE_DPAD_LEFT:                smoothScrollBy(-1);                return true;            case KeyEvent.KEYCODE_DPAD_RIGHT:                smoothScrollBy(1);                return true;            default:                return super.onKeyDown(keyCode, event);        }    }    @Override    protected boolean dispatchHoverEvent(MotionEvent event) {        if (touchHelper.dispatchHoverEvent(event)) {            return true;        }        return super.dispatchHoverEvent(event);    }    @Override    public void computeScroll() {        computeScrollX();    }    @Override    public void getFocusedRect(Rect r) {        super.getFocusedRect(r); // TODO this should only be current item    }    public void setOnItemSelectedListener(OnItemSelected onItemSelected) {        this.onItemSelected = onItemSelected;    }    public void setOnItemClickedListener(OnItemClicked onItemClicked) {        this.onItemClicked = onItemClicked;    }    public int getSelectedItem() {        int x = getScrollX();        return getPositionFromCoordinates(x);    }    public void setSelectedItem(int index) {        selectedItem = index;        scrollToItem(index);    }    /**     * 设置选中项     *     * @param item     */    public void setSelectedItem(String item) {        selectedItem = getIndex(item);        scrollToItem(selectedItem);    }    /**     * 根据数据返回相应的下标     *     * @param item     * @return     */    private int getIndex(String item) {        for (int i = 0; i < arrays.length - 1; i++) {            if (arrays[i].equals(item))                return i;        }        return 0;    }    public int getMarqueeRepeatLimit() {        return marqueeRepeatLimit;    }    public void setMarqueeRepeatLimit(int marqueeRepeatLimit) {        this.marqueeRepeatLimit = marqueeRepeatLimit;    }    /**     * @return Number of items on each side of current item.     */    public int getSideItems() {        return sideItems;    }    public void setSideItems(int sideItems) {        if (this.sideItems < 0) {            throw new IllegalArgumentException("Number of items on each side must be grater or equal to 0.");        } else if (this.sideItems != sideItems) {            this.sideItems = sideItems;            calculateItemSize(getWidth(), getHeight());        }    }    /**     * @return     */    public CharSequence[] getValues() {        return values;    }    /**     * Sets values to choose from     *     * @param values New values to choose from     */    public void setValues(CharSequence[] values) {        if (this.values != values) {            this.values = values;            if (this.values != null) {                layouts = new BoringLayout[this.values.length];                for (int i = 0; i < layouts.length; i++) {                    layouts[i] = new BoringLayout(this.values[i], textPaint, itemWidth, Layout.Alignment.ALIGN_CENTER,                            1f, 1f, boringMetrics, false, ellipsize, itemWidth);                }            } else {                layouts = new BoringLayout[0];            }            // start marque only if has already been measured            if (getWidth() > 0) {                startMarqueeIfNeeded();            }            requestLayout();            invalidate();        }    }    @Override    protected void onRestoreInstanceState(Parcelable state) {        if (!(state instanceof SavedState)) {            super.onRestoreInstanceState(state);            return;        }        SavedState ss = (SavedState) state;        super.onRestoreInstanceState(ss.getSuperState());        setSelectedItem(ss.mSelItem);    }    @Override    protected Parcelable onSaveInstanceState() {        Parcelable superState = super.onSaveInstanceState();        SavedState savedState = new SavedState(superState);        savedState.mSelItem = selectedItem;        return savedState;    }    @Override    public void setOverScrollMode(int overScrollMode) {        if (overScrollMode != OVER_SCROLL_NEVER) {            Context context = getContext();            leftEdgeEffect = new EdgeEffect(context);            rightEdgeEffect = new EdgeEffect(context);        } else {            leftEdgeEffect = null;            rightEdgeEffect = null;        }        super.setOverScrollMode(overScrollMode);    }    public TextUtils.TruncateAt getEllipsize() {        return ellipsize;    }    public void setEllipsize(TextUtils.TruncateAt ellipsize) {        if (this.ellipsize != ellipsize) {            this.ellipsize = ellipsize;            remakeLayout();            invalidate();        }    }    @Override    protected void onOverScrolled(int scrollX, int scrollY, boolean clampedX, boolean clampedY) {        super.scrollTo(scrollX, scrollY);        if (!flingScrollerX.isFinished() && clampedX) {            flingScrollerX.springBack(scrollX, scrollY, 0, getScrollRange(), 0, 0);        }    }    @Override    protected void drawableStateChanged() {        super.drawableStateChanged(); //TODO    }    private int getPositionFromTouch(float x) {        return getPositionFromCoordinates((int) (getScrollX() - (itemWidth + dividerSize) * (sideItems + .5f) + x));    }    private void computeScrollX() {        OverScroller scroller = flingScrollerX;        if (scroller.isFinished()) {            scroller = adjustScrollerX;            if (scroller.isFinished()) {                return;            }        }        if (scroller.computeScrollOffset()) {            int currentScrollerX = scroller.getCurrX();            if (previousScrollerX == Integer.MIN_VALUE) {                previousScrollerX = scroller.getStartX();            }            int range = getScrollRange();            if (previousScrollerX >= 0 && currentScrollerX < 0) {                leftEdgeEffect.onAbsorb((int) scroller.getCurrVelocity());            } else if (previousScrollerX <= range && currentScrollerX > range) {                rightEdgeEffect.onAbsorb((int) scroller.getCurrVelocity());            }            overScrollBy(currentScrollerX - previousScrollerX, 0, previousScrollerX, getScrollY(),                    getScrollRange(), 0, overscrollDistance, 0, false);            previousScrollerX = currentScrollerX;            if (scroller.isFinished()) {                onScrollerFinishedX(scroller);            }            postInvalidate();//            postInvalidateOnAnimation(); // TODO        }    }    private void flingX(int velocityX) {        previousScrollerX = Integer.MIN_VALUE;        flingScrollerX.fling(getScrollX(), getScrollY(), -velocityX, 0, 0,                (int) (itemWidth + dividerSize) * (values.length - 1), 0, 0, getWidth() / 2, 0);        invalidate();    }    private void adjustToNearestItemX() {        int x = getScrollX();        int item = Math.round(x / (itemWidth + dividerSize * 1f));        if (item < 0) {            item = 0;        } else if (item > values.length) {            item = values.length;        }        selectedItem = item;        int itemX = (itemWidth + (int) dividerSize) * item;        int deltaX = itemX - x;        previousScrollerX = Integer.MIN_VALUE;        adjustScrollerX.startScroll(x, 0, deltaX, 0, SELECTOR_ADJUSTMENT_DURATION_MILLIS);        invalidate();    }    private void calculateItemSize(int w, int h) {        int items = sideItems * 2 + 1;        int totalPadding = ((int) dividerSize * (items - 1));        itemWidth = (w - totalPadding) / items;        itemClipBounds = new RectF(0, 0, itemWidth, h);        itemClipBoundsOffset = new RectF(itemClipBounds);        scrollToItem(selectedItem);        remakeLayout();        startMarqueeIfNeeded();    }    private void onScrollerFinishedX(OverScroller scroller) {        if (scroller == flingScrollerX) {            finishScrolling();        }    }    private void finishScrolling() {        adjustToNearestItemX();        scrollingX = false;        startMarqueeIfNeeded();        // post to the UI Thread to avoid potential interference with the OpenGL Thread        if (onItemSelected != null) {            post(new Runnable() {                @Override                public void run() {//                    onItemSelected.onItemSelected(getPositionFromCoordinates(getScrollX()));                    onItemSelected.onItemSelected(arrays[getPositionFromCoordinates(getScrollX())]);                }            });        }    }    private void startMarqueeIfNeeded() {        stopMarqueeIfNeeded();        int item = getSelectedItem();        if (layouts != null && layouts.length > item) {            Layout layout = layouts[item];            if (ellipsize == TextUtils.TruncateAt.MARQUEE                    && itemWidth < layout.getLineWidth(0)) {                marquee = new Marquee(this, layout, isRtl(values[item]));                marquee.start(marqueeRepeatLimit);            }        }    }    private void stopMarqueeIfNeeded() {        if (marquee != null) {            marquee.stop();            marquee = null;        }    }    private int getPositionOnScreen(float x) {        return (int) (x / (itemWidth + dividerSize));    }    private void smoothScrollBy(int i) {        int deltaMoveX = (itemWidth + (int) dividerSize) * i;        deltaMoveX = getRelativeInBound(deltaMoveX);        previousScrollerX = Integer.MIN_VALUE;        flingScrollerX.startScroll(getScrollX(), 0, deltaMoveX, 0);        stopMarqueeIfNeeded();        invalidate();    }    /**     * Calculates color for specific position on time picker     * 修改选中颜色     *     * @param scrollX     * @return     */    private int getColor(int scrollX, int position) {        int itemWithPadding = (int) (itemWidth + dividerSize);        float proportion = Math.abs(((1f * scrollX % itemWithPadding) / 2) / (itemWithPadding / 2f));        if (proportion > .5) {            proportion = (proportion - .5f);        } else {            proportion = .5f - proportion;        }        proportion *= 2;        int defaultColor;        int selectedColor;        if (pressedItem == position) {            defaultColor = textColor.getColorForState(new int[]{android.R.attr.state_pressed}, textColor.getDefaultColor());//            selectedColor = textColor.getColorForState(new int[]{android.R.attr.state_pressed, android.R.attr.state_selected}, defaultColor);            selectedColor = Color.RED;        } else {            defaultColor = textColor.getDefaultColor();//            selectedColor = textColor.getColorForState(new int[]{android.R.attr.state_selected}, defaultColor);            selectedColor = Color.RED;        }        return (Integer) new ArgbEvaluator().evaluate(proportion, selectedColor, defaultColor);    }    /**     * Sets text size for items     *     * @param size New item text size in px.     */    private void setTextSize(float size) {        if (size != textPaint.getTextSize()) {            textPaint.setTextSize(size);            requestLayout();            invalidate();        }    }    /**     * Calculates item from x coordinate position.     *     * @param x Scroll position to calculate.     * @return Selected item from scrolling position in {param x}     */    private int getPositionFromCoordinates(int x) {        return Math.round(x / (itemWidth + dividerSize));    }    /**     * Scrolls to specified item.     *     * @param index Index of an item to scroll to     */    private void scrollToItem(int index) {        scrollTo((itemWidth + (int) dividerSize) * index, 0);        // invalidate() not needed because scrollTo() already invalidates the view    }    /**     * Calculates relative horizontal scroll position to be within our scroll bounds.     *     * @param x Relative scroll position to calculate     * @return Current scroll position + {param x} if is within our scroll bounds, otherwise it     * will return min/max scroll position.     */    private int getRelativeInBound(int x) {        int scrollX = getScrollX();        return getInBoundsX(scrollX + x) - scrollX;    }    /**     * Calculates x scroll position that is still in range of view scroller     *     * @param x Scroll position to calculate.     * @return {param x} if is within bounds of over scroller, otherwise it will return min/max     * value of scoll position.     */    private int getInBoundsX(int x) {        if (x < 0) {            x = 0;        } else if (x > ((itemWidth + (int) dividerSize) * (values.length - 1))) {            x = ((itemWidth + (int) dividerSize) * (values.length - 1));        }        return x;    }    private int getScrollRange() {        int scrollRange = 0;        if (values != null && values.length != 0) {            scrollRange = Math.max(0, ((itemWidth + (int) dividerSize) * (values.length - 1)));        }        return scrollRange;    }    public interface OnItemSelected {        //        public void onItemSelected(int index);        public void onItemSelected(String item);    }    public interface OnItemClicked {        public void onItemClicked(int index);    }    private static final class Marquee extends Handler {        // TODO: Add an option to configure this        private static final float MARQUEE_DELTA_MAX = 0.07f;        private static final int MARQUEE_DELAY = 1200;        private static final int MARQUEE_RESTART_DELAY = 1200;        private static final int MARQUEE_RESOLUTION = 1000 / 30;        private static final int MARQUEE_PIXELS_PER_SECOND = 30;        private static final byte MARQUEE_STOPPED = 0x0;        private static final byte MARQUEE_STARTING = 0x1;        private static final byte MARQUEE_RUNNING = 0x2;        private static final int MESSAGE_START = 0x1;        private static final int MESSAGE_TICK = 0x2;        private static final int MESSAGE_RESTART = 0x3;        private final WeakReference<HorizontalPicker> mView;        private final WeakReference<Layout> mLayout;        private byte mStatus = MARQUEE_STOPPED;        private final float mScrollUnit;        private float mMaxScroll;        private float mMaxFadeScroll;        private float mGhostStart;        private float mGhostOffset;        private float mFadeStop;        private int mRepeatLimit;        private float mScroll;        private boolean mRtl;        Marquee(HorizontalPicker v, Layout l, boolean rtl) {            final float density = v.getContext().getResources().getDisplayMetrics().density;            float scrollUnit = (MARQUEE_PIXELS_PER_SECOND * density) / MARQUEE_RESOLUTION;            if (rtl) {                mScrollUnit = -scrollUnit;            } else {                mScrollUnit = scrollUnit;            }            mView = new WeakReference<HorizontalPicker>(v);            mLayout = new WeakReference<Layout>(l);            mRtl = rtl;        }        @Override        public void handleMessage(Message msg) {            switch (msg.what) {                case MESSAGE_START:                    mStatus = MARQUEE_RUNNING;                    tick();                    break;                case MESSAGE_TICK:                    tick();                    break;                case MESSAGE_RESTART:                    if (mStatus == MARQUEE_RUNNING) {                        if (mRepeatLimit >= 0) {                            mRepeatLimit--;                        }                        start(mRepeatLimit);                    }                    break;            }        }        void tick() {            if (mStatus != MARQUEE_RUNNING) {                return;            }            removeMessages(MESSAGE_TICK);            final HorizontalPicker view = mView.get();            final Layout layout = mLayout.get();            if (view != null && layout != null && (view.isFocused() || view.isSelected())) {                mScroll += mScrollUnit;                if (Math.abs(mScroll) > mMaxScroll) {                    mScroll = mMaxScroll;                    if (mRtl) {                        mScroll *= -1;                    }                    sendEmptyMessageDelayed(MESSAGE_RESTART, MARQUEE_RESTART_DELAY);                } else {                    sendEmptyMessageDelayed(MESSAGE_TICK, MARQUEE_RESOLUTION);                }                view.invalidate();            }        }        void stop() {            mStatus = MARQUEE_STOPPED;            removeMessages(MESSAGE_START);            removeMessages(MESSAGE_RESTART);            removeMessages(MESSAGE_TICK);            resetScroll();        }        private void resetScroll() {            mScroll = 0.0f;            final HorizontalPicker view = mView.get();            if (view != null) view.invalidate();        }        void start(int repeatLimit) {            if (repeatLimit == 0) {                stop();                return;            }            mRepeatLimit = repeatLimit;            final HorizontalPicker view = mView.get();            final Layout layout = mLayout.get();            if (view != null && layout != null) {                mStatus = MARQUEE_STARTING;                mScroll = 0.0f;                final int textWidth = view.itemWidth;                final float lineWidth = layout.getLineWidth(0);                final float gap = textWidth / 3.0f;                mGhostStart = lineWidth - textWidth + gap;                mMaxScroll = mGhostStart + textWidth;                mGhostOffset = lineWidth + gap;                mFadeStop = lineWidth + textWidth / 6.0f;                mMaxFadeScroll = mGhostStart + lineWidth + lineWidth;                if (mRtl) {                    mGhostOffset *= -1;                }                view.invalidate();                sendEmptyMessageDelayed(MESSAGE_START, MARQUEE_DELAY);            }        }        float getGhostOffset() {            return mGhostOffset;        }        float getScroll() {            return mScroll;        }        float getMaxFadeScroll() {            return mMaxFadeScroll;        }        boolean shouldDrawLeftFade() {            return mScroll <= mFadeStop;        }        boolean shouldDrawGhost() {            return mStatus == MARQUEE_RUNNING && Math.abs(mScroll) > mGhostStart;        }        boolean isRunning() {            return mStatus == MARQUEE_RUNNING;        }        boolean isStopped() {            return mStatus == MARQUEE_STOPPED;        }    }    public static class SavedState extends BaseSavedState {        private int mSelItem;        public SavedState(Parcelable superState) {            super(superState);        }        private SavedState(Parcel in) {            super(in);            mSelItem = in.readInt();        }        @Override        public void writeToParcel(Parcel dest, int flags) {            super.writeToParcel(dest, flags);            dest.writeInt(mSelItem);        }        @Override        public String toString() {            return "HorizontalPicker.SavedState{"                    + Integer.toHexString(System.identityHashCode(this))                    + " selItem=" + mSelItem                    + "}";        }        @SuppressWarnings("hiding")        public static final Creator<SavedState> CREATOR                = new Creator<SavedState>() {            public SavedState createFromParcel(Parcel in) {                return new SavedState(in);            }            public SavedState[] newArray(int size) {                return new SavedState[size];            }        };    }    private static class PickerTouchHelper extends ExploreByTouchHelper {        private HorizontalPicker mPicker;        public PickerTouchHelper(HorizontalPicker picker) {            super(picker);            mPicker = picker;        }        @Override        protected int getVirtualViewAt(float x, float y) {            float itemWidth = mPicker.itemWidth + mPicker.dividerSize;            float position = mPicker.getScrollX() + x - itemWidth * mPicker.sideItems;            float item = position / itemWidth;            if (item < 0 || item > mPicker.values.length) {                return INVALID_ID;            }            return (int) item;        }        @Override        protected void getVisibleVirtualViews(List<Integer> virtualViewIds) {            float itemWidth = mPicker.itemWidth + mPicker.dividerSize;            float position = mPicker.getScrollX() - itemWidth * mPicker.sideItems;            int first = (int) (position / itemWidth);            int items = mPicker.sideItems * 2 + 1;            if (position % itemWidth != 0) { // if start next item is starting to appear on screen                items++;            }            if (first < 0) {                items += first;                first = 0;            } else if (first + items > mPicker.values.length) {                items = mPicker.values.length - first;            }            for (int i = 0; i < items; i++) {                virtualViewIds.add(first + i);            }        }        @Override        protected void onPopulateEventForVirtualView(int virtualViewId, AccessibilityEvent event) {            event.setContentDescription(mPicker.values[virtualViewId]);        }        @Override        protected void onPopulateNodeForVirtualView(int virtualViewId, AccessibilityNodeInfoCompat node) {            float itemWidth = mPicker.itemWidth + mPicker.dividerSize;            float scrollOffset = mPicker.getScrollX() - itemWidth * mPicker.sideItems;            int left = (int) (virtualViewId * itemWidth - scrollOffset);            int right = left + mPicker.itemWidth;            node.setContentDescription(mPicker.values[virtualViewId]);            node.setBoundsInParent(new Rect(left, 0, right, mPicker.getHeight()));            node.addAction(AccessibilityNodeInfoCompat.ACTION_CLICK);        }        @Override        protected boolean onPerformActionForVirtualView(int virtualViewId, int action, Bundle arguments) {            return false;        }    }}
自定义 
MyScaleView
package com.example.yangbin.pickm;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Path;import android.util.AttributeSet;import android.view.View;/** * Created by Administrator on 2016/9/2 0002. */public class MyScaleView extends View {    private Paint paint;    private int mWidth;    private int mHeight;    public MyScaleView(Context context) {        super(context);        init();    }    public MyScaleView(Context context, AttributeSet attrs) {        super(context, attrs);        init();    }    public MyScaleView(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);    }    private void init() {        paint = new Paint();        paint.setColor(Color.parseColor("#7E7E7E"));        paint.setAntiAlias(true);        paint.setStrokeWidth(2);    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        mWidth = getWidth();        mHeight = getHeight();        // 画一条线        canvas.drawLine(0f, mHeight, mWidth, mHeight, paint);        Path path = new Path();        path.moveTo(mWidth / 2, mHeight - 30);// 此点为多边形的起点        path.lineTo(mWidth / 2 - 20, mHeight);        path.lineTo(mWidth / 2 + 20, mHeight);        path.close(); // 使这些点构成封闭的多边形        canvas.drawPath(path, paint);    }    private int dp2px(int value) {        float v = getContext().getResources().getDisplayMetrics().density;        return (int) (v * value + 0.5f);    }}