仿网易新闻的顶部导航指示器

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仿网易新闻的顶部导航指示器


我们知道,页面导航器(Navigator)在几乎所有的项目中都会用到,平时大多数时候为了节省时间,都会直接在github上面拿别人的开源项目来用,最近自己在复习自定义View,就尝试封装了一下,源码参考项目PagerSlidingTabStrip

转载请注明原博客地址:

大家先来看一下效果图

基于文字的页面导航器

基于图片的页面导航器

使用方法

主要步骤分为三步

1)在xml文件里面

<com.xujun.viewpagertabindicator.TabPagerIndicator    android:id="@+id/pagerIndicator"    android:layout_width="match_parent"    android:layout_height="50dp"/><android.support.v4.view.ViewPager    android:layout_weight="1"    android:id="@+id/viewPager"    android:layout_width="match_parent"    android:layout_height="0dp"></android.support.v4.view.ViewPager>

2)在代码里面找到相应的控件

 mPagerIndicator = (TabPagerIndicator) findViewById(R.id.pagerIndicator); mViewPager = (ViewPager) findViewById(R.id.viewPager);

3)初始化ViewPager的Adapter和将mViewPager和我们的mPagerIndicator绑定

//必须先给ViewPager设置适配器mViewPager.setAdapter(mPagerAdapter);//接着将mViewPage和我们的mPagerIndicator绑定mPagerIndicator.setViewPager(mViewPager);

注意事项,

  • 如果是文字标题导航的,我们只需重写在适配器里面重写getPageTitle这个方法
public CharSequence getPageTitle(int position) {        return titles[position];}
  • 如果是图标导航的,我们的适配器需要实现这个借口TabPagerIndicator.IconTabProvider,并重写里面的public int getPageIconResId(int position)这个方法
public class BaseIconAdapter extends FragmentPagerAdapter implements TabPagerIndicator.IconTabProvider {    //省略了若干方法,有兴趣可以去看一下例子    @Override    public int getPageIconResId(int position) {        return resIds[position];    }}
  • 我们可以通过setIndicatorMode(IndicatorMode indicatorMode)这个方法设置不同的下滑线样式
mPagerIndicator.setIndicatorMode(TabPagerIndicator.IndicatorMode.MODE_WEIGHT_EXPAND_NOSAME,            true);

mPagerIndicator.setIndicatorMode(TabPagerIndicator.IndicatorMode.MODE_WEIGHT_EXPAND_SAME,            true);

关于下划线的 颜色,字体的颜色与大小的设置,请参照源码设置,这里就不列举了


源码分析

大家先来看一下源码吧

public class TabPagerIndicator extends HorizontalScrollView {    public interface IconTabProvider {        int getPageIconResId(int position);    }    // @formatter:off    private static final int[] ATTRS = new int[]{            android.R.attr.textSize,            android.R.attr.textColor    };    // @formatter:on    private LinearLayout.LayoutParams wrapTabLayoutParams;    private LinearLayout.LayoutParams expandedTabLayoutParams;    private final PageListener pageListener = new PageListener();    public OnPageChangeListener delegatePageListener;    private LinearLayout tabsContainer;    private ViewPager pager;    private int tabCount;    private static final String TAG = "xujun";    private int currentPosition = 0;    private float currentPositionOffset = 0f;    private Paint rectPaint;    private Paint dividerPaint;    private int indicatorColor = 0xFF666666;    private int underlineColor = 0x1A000000;    private int dividerColor = 0x1A000000;    //表示是否扩展    private boolean isExpand = false;    //表示下滑线的长度是否与标题字体的长度一样    private boolean isSame = false;    private boolean textAllCaps = true;    private int scrollOffset = 52;    private int indicatorHeight = 8;    private int underlineHeight = 2;    private int dividerPadding = 12;    //表示自己之间的间隔    private int horizontalPadding = 24;    private int verticalPadding = 10;    private int dividerWidth = 1;    private int tabTextSize = 12;    private int tabTextColor = 0xFF666666;    private Typeface tabTypeface = null;    private int tabTypefaceStyle = Typeface.BOLD;    private int lastScrollX = -1;    private int tabBackgroundResId = R.drawable.background_tab;    //Indicator的样式    private IndicatorMode curMode = IndicatorMode.MODE_WRAP_EXPAND_SAME;    private Locale locale;    public TabPagerIndicator(Context context) {        this(context, null);    }    public TabPagerIndicator(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public TabPagerIndicator(Context context, AttributeSet attrs, int defStyle) {        super(context, attrs, defStyle);        setFillViewport(true);        setWillNotDraw(false);        tabsContainer = new LinearLayout(context);        tabsContainer.setOrientation(LinearLayout.HORIZONTAL);        tabsContainer.setLayoutParams(new LayoutParams(LayoutParams.MATCH_PARENT,                LayoutParams.MATCH_PARENT));        addView(tabsContainer);        //根据IndicatorMode初始化各个变量        setIndicatorMode(curMode);        //初始化自定义属性        obtainAttrs(context, attrs);        rectPaint = new Paint();        rectPaint.setAntiAlias(true);        rectPaint.setStyle(Style.FILL);        dividerPaint = new Paint();        dividerPaint.setAntiAlias(true);        dividerPaint.setStrokeWidth(dividerWidth);        wrapTabLayoutParams = new LinearLayout.LayoutParams(LayoutParams.WRAP_CONTENT,                LayoutParams.MATCH_PARENT);        expandedTabLayoutParams = new LinearLayout.LayoutParams(0, LayoutParams.MATCH_PARENT, 1.0f);        if (locale == null) {            locale = getResources().getConfiguration().locale;        }    }    public void setIndicatorMode(IndicatorMode indicatorMode) {        this.setIndicatorMode(indicatorMode, false);    }    public void setIndicatorMode(IndicatorMode indicatorMode, boolean isNotify) {        switch (indicatorMode) {            case MODE_WRAP_EXPAND_SAME:                isExpand = false;                isSame = true;                break;            case MODE_WRAP_EXPAND_NOSAME:                isExpand = false;                isSame = false;                break;            case MODE_WEIGHT_EXPAND_NOSAME:                isExpand = true;                isSame = false;                break;            case MODE_WEIGHT_EXPAND_SAME:                isExpand = true;                isSame = true;                break;        }        this.curMode = indicatorMode;        if (isNotify) {            notifyDataSetChanged();        }    }    private void obtainAttrs(Context context, AttributeSet attrs) {        DisplayMetrics dm = getResources().getDisplayMetrics();        scrollOffset = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, scrollOffset,                dm);        indicatorHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,                indicatorHeight, dm);        underlineHeight = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,                underlineHeight, dm);        dividerPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,                dividerPadding, dm);        horizontalPadding = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,                horizontalPadding, dm);        dividerWidth = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP, dividerWidth,                dm);        tabTextSize = (int) TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP, tabTextSize, dm);        // get system attrs (android:textSize and android:textColor)        TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);        tabTextSize = a.getDimensionPixelSize(0, tabTextSize);        tabTextColor = a.getColor(1, tabTextColor);        a.recycle();        // get custom attrs        a = context.obtainStyledAttributes(attrs, R.styleable.TabPagerIndicator);        indicatorColor = a.getColor(R.styleable.TabPagerIndicator_pstsIndicatorColor,                indicatorColor);        underlineColor = a.getColor(R.styleable.TabPagerIndicator_pstsUnderlineColor,                underlineColor);        dividerColor = a.getColor(R.styleable.TabPagerIndicator_pstsDividerColor, dividerColor);        indicatorHeight = a.getDimensionPixelSize(R.styleable                .TabPagerIndicator_pstsIndicatorHeight, indicatorHeight);        underlineHeight = a.getDimensionPixelSize(R.styleable                .TabPagerIndicator_pstsUnderlineHeight, underlineHeight);        dividerPadding = a.getDimensionPixelSize(R.styleable                .TabPagerIndicator_pstsDividerPadding, dividerPadding);        horizontalPadding = a.getDimensionPixelSize(R.styleable                .TabPagerIndicator_pstsTabPaddingLeftRight, horizontalPadding);        tabBackgroundResId = a.getResourceId(R.styleable.TabPagerIndicator_pstsTabBackground,                tabBackgroundResId);        isExpand = a.getBoolean(R.styleable.TabPagerIndicator_pstsShouldExpand,                isExpand);        scrollOffset = a.getDimensionPixelSize(R.styleable.TabPagerIndicator_pstsScrollOffset,                scrollOffset);        textAllCaps = a.getBoolean(R.styleable.TabPagerIndicator_pstsTextAllCaps, textAllCaps);        a.recycle();    }    public void setViewPager(ViewPager pager) {        this.pager = pager;        if (pager.getAdapter() == null) {            throw new IllegalStateException("ViewPager does not have adapter instance.");        }        pager.addOnPageChangeListener(pageListener);        notifyDataSetChanged();    }    public void addOnPageChangeListener(OnPageChangeListener listener) {        this.delegatePageListener = listener;    }    public void notifyDataSetChanged() {        //先移除掉所有的View ,防止重复添加        tabsContainer.removeAllViews();        tabCount = pager.getAdapter().getCount();        for (int i = 0; i < tabCount; i++) {            //区分是文字还是Icon的导航            if (pager.getAdapter() instanceof IconTabProvider) {                addIconTab(i, ((IconTabProvider) pager.getAdapter()).getPageIconResId(i));            } else {                addTextTab(i, pager.getAdapter().getPageTitle(i).toString());            }        }        updateTabStyles();        //监听视图树,在绘制完毕后调用相关的方法完成初始化工作        getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {            @SuppressWarnings("deprecation")            @SuppressLint("NewApi")            @Override            public void onGlobalLayout() {                if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {                    getViewTreeObserver().removeGlobalOnLayoutListener(this);                } else {                    getViewTreeObserver().removeOnGlobalLayoutListener(this);                }                currentPosition = pager.getCurrentItem();                scrollToChild(currentPosition, 0);            }        });    }    private void addTextTab(final int position, String title) {        TextView tab = new TextView(getContext());        tab.setText(title);        tab.setGravity(Gravity.CENTER);        tab.setSingleLine();        addTab(position, tab);    }    private void addIconTab(final int position, int resId) {        ImageButton tab = new ImageButton(getContext());        tab.setImageResource(resId);        addTab(position, tab);    }    //添加孩子    private void addTab(final int position, View tab) {        tab.setFocusable(true);        // 设置监听        tab.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                pager.setCurrentItem(position);            }        });        // 这里我们下划线的 高度是否与文字的长度保持一致,是通过给孩子设置padding或者margin实现的        //  注意与onDraw里面的逻辑结合起来        if (!isSame) {            tab.setPadding(horizontalPadding, verticalPadding, horizontalPadding, verticalPadding);            wrapTabLayoutParams.setMargins(0, 0, 0, 0);            expandedTabLayoutParams.setMargins(0, 0, 0, 0);        } else {            wrapTabLayoutParams.setMargins(horizontalPadding, verticalPadding,                    horizontalPadding, verticalPadding);            expandedTabLayoutParams.setMargins(horizontalPadding, verticalPadding,                    horizontalPadding, verticalPadding);        }        //根据是否可以扩展来设置不同的layoutParams        tabsContainer.addView(tab, position, isExpand ? expandedTabLayoutParams :                wrapTabLayoutParams);    }    private void updateTabStyles() {        for (int i = 0; i < tabCount; i++) {            View v = tabsContainer.getChildAt(i);            v.setBackgroundResource(tabBackgroundResId);            if (v instanceof TextView) {                TextView tab = (TextView) v;                tab.setTextSize(TypedValue.COMPLEX_UNIT_PX, tabTextSize);                tab.setTypeface(tabTypeface, tabTypefaceStyle);                tab.setTextColor(tabTextColor);                // setAllCaps() is only available from API 14, so the upper case is made manually                // if we are on a pre-ICS-build                if (textAllCaps) {                    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {                        tab.setAllCaps(true);                    } else {                        tab.setText(tab.getText().toString().toUpperCase(locale));                    }                }            }        }    }    // 调用这个方法是HorizontalScrollView滑动到相应的位置    private void scrollToChild(int position, int offset) {        if (tabCount == 0) {            return;        }        int newScrollX;        View child = tabsContainer.getChildAt(position);        int left = child.getLeft();        if (isSame) {            newScrollX = left + offset - horizontalPadding;        } else {            newScrollX = left + offset;        }        if (position > 0 || offset > 0) {            newScrollX -= scrollOffset;        }        Log.i(TAG, "scrollToChild:newScrollX=" + newScrollX);        if (newScrollX != lastScrollX) {            lastScrollX = newScrollX;            scrollTo(newScrollX, 0);        }    }    @Override    protected void onDraw(Canvas canvas) {        super.onDraw(canvas);        if (isInEditMode() || tabCount == 0) {            return;        }        final int height = getHeight();        // draw indicator line        rectPaint.setColor(indicatorColor);        // default: line below current tab        View currentTab = tabsContainer.getChildAt(currentPosition);        float lineLeft = currentTab.getLeft();        float lineRight = currentTab.getRight();        // if there is an offset, start interpolating left and right coordinates between current        // and next tab        if (currentPositionOffset > 0f && currentPosition < tabCount - 1) {            View nextTab = tabsContainer.getChildAt(currentPosition + 1);            final float nextTabLeft = nextTab.getLeft();            final float nextTabRight = nextTab.getRight();            lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset) *                    lineLeft);            lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset) *                    lineRight);        }        canvas.drawRect(lineLeft, height - indicatorHeight, lineRight, height, rectPaint);        // draw underline        rectPaint.setColor(underlineColor);        canvas.drawRect(0, height - underlineHeight, tabsContainer.getWidth(), height, rectPaint);        // draw divider        dividerPaint.setColor(dividerColor);        for (int i = 0; i < tabCount - 1; i++) {            View tab = tabsContainer.getChildAt(i);            if (!isSame) {                canvas.drawLine(tab.getRight(), dividerPadding, tab.getRight(),                        height - dividerPadding, dividerPaint);            } else {                canvas.drawLine(tab.getRight() + horizontalPadding, dividerPadding,                        tab.getRight() + horizontalPadding, height - dividerPadding, dividerPaint);            }        }    }    private class PageListener implements OnPageChangeListener {        @Override        public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {            currentPosition = position;            currentPositionOffset = positionOffset;            View child = tabsContainer.getChildAt(position);            int width = child.getWidth();            if (isSame) {                width += horizontalPadding * 2;            }            Log.i(TAG, "onPageScrolled:width=" + width);            //  调用这个方法是HorizontalScrollView滑动到相应的位置            scrollToChild(position, (int) (positionOffset * width));            //调用这个方法重新绘制            invalidate();            if (delegatePageListener != null) {                delegatePageListener.onPageScrolled(position, positionOffset, positionOffsetPixels);            }        }        @Override        public void onPageScrollStateChanged(int state) {            if (delegatePageListener != null) {                delegatePageListener.onPageScrollStateChanged(state);            }        }        @Override        public void onPageSelected(int position) {            if (delegatePageListener != null) {                delegatePageListener.onPageSelected(position);            }        }    }    public void setIndicatorColor(int indicatorColor) {        this.indicatorColor = indicatorColor;        invalidate();    }    public void setIndicatorColorResource(int resId) {        this.indicatorColor = getResources().getColor(resId);        invalidate();    }    public int getIndicatorColor() {        return this.indicatorColor;    }    public void setIndicatorHeight(int indicatorLineHeightPx) {        this.indicatorHeight = indicatorLineHeightPx;        invalidate();    }    public int getIndicatorHeight() {        return indicatorHeight;    }    public void setUnderlineColor(int underlineColor) {        this.underlineColor = underlineColor;        invalidate();    }    public void setUnderlineColorResource(int resId) {        this.underlineColor = getResources().getColor(resId);        invalidate();    }    public int getUnderlineColor() {        return underlineColor;    }    public void setDividerColor(int dividerColor) {        this.dividerColor = dividerColor;        invalidate();    }    public void setDividerColorResource(int resId) {        this.dividerColor = getResources().getColor(resId);        invalidate();    }    public int getDividerColor() {        return dividerColor;    }    public void setUnderlineHeight(int underlineHeightPx) {        this.underlineHeight = underlineHeightPx;        invalidate();    }    public int getUnderlineHeight() {        return underlineHeight;    }    public void setDividerPadding(int dividerPaddingPx) {        this.dividerPadding = dividerPaddingPx;        invalidate();    }    public int getDividerPadding() {        return dividerPadding;    }    public void setScrollOffset(int scrollOffsetPx) {        this.scrollOffset = scrollOffsetPx;        invalidate();    }    public int getScrollOffset() {        return scrollOffset;    }    public void setExpand(boolean expand) {        this.isExpand = expand;        requestLayout();    }    public boolean getExpand() {        return isExpand;    }    public boolean isTextAllCaps() {        return textAllCaps;    }    public void setAllCaps(boolean textAllCaps) {        this.textAllCaps = textAllCaps;    }    public void setTextSize(int textSizePx) {        this.tabTextSize = textSizePx;        updateTabStyles();    }    public int getTextSize() {        return tabTextSize;    }    public void setTextColor(int textColor) {        this.tabTextColor = textColor;        updateTabStyles();    }    public void setTextColorResource(int resId) {        this.tabTextColor = getResources().getColor(resId);        updateTabStyles();    }    public int getTextColor() {        return tabTextColor;    }    public void setTypeface(Typeface typeface, int style) {        this.tabTypeface = typeface;        this.tabTypefaceStyle = style;        updateTabStyles();    }    public void setTabBackground(int resId) {        this.tabBackgroundResId = resId;    }    public int getTabBackground() {        return tabBackgroundResId;    }    public void setTabPaddingLeftRight(int paddingPx) {        this.horizontalPadding = paddingPx;        updateTabStyles();    }    public int getTabPaddingLeftRight() {        return horizontalPadding;    }    @Override    public void onRestoreInstanceState(Parcelable state) {        SavedState savedState = (SavedState) state;        super.onRestoreInstanceState(savedState.getSuperState());        currentPosition = savedState.currentPosition;        requestLayout();    }    @Override    public Parcelable onSaveInstanceState() {        Parcelable superState = super.onSaveInstanceState();        SavedState savedState = new SavedState(superState);        savedState.currentPosition = currentPosition;        return savedState;    }    //用来保存状态    static class SavedState extends BaseSavedState {        int currentPosition;        public SavedState(Parcelable superState) {            super(superState);        }        private SavedState(Parcel in) {            super(in);            currentPosition = in.readInt();        }        @Override        public void writeToParcel(Parcel dest, int flags) {            super.writeToParcel(dest, flags);            dest.writeInt(currentPosition);        }        public static final Creator<SavedState> CREATOR = new Creator<SavedState>() {            @Override            public SavedState createFromParcel(Parcel in) {                return new SavedState(in);            }            @Override            public SavedState[] newArray(int size) {                return new SavedState[size];            }        };    }    /**     * 定义4种模式     */    public enum IndicatorMode {        // 给枚举传入自定义的int值        MODE_WRAP_EXPAND_SAME(1),// 可扩展,导航线跟标题相等        MODE_WRAP_EXPAND_NOSAME(2),// 可扩展,导标不相等        MODE_WEIGHT_EXPAND_SAME(3),// 可扩展,导航线跟标题相等        MODE_WEIGHT_EXPAND_NOSAME(4);// 可扩展,导标不相等        private int value;        IndicatorMode(int value) {            this.value = value;        }        public int getValue() {            return value;        }    }}

思路主要 可以分为以下几个步骤

1)在构造方法里面初始化各种工作,包括一些自定义属性,画笔等等

public TabPagerIndicator(Context context, AttributeSet attrs, int defStyle) {    super(context, attrs, defStyle);   //初始化各种工作    //根据IndicatorMode初始化各个变量    setIndicatorMode(curMode);    //初始化自定义属性    obtainAttrs(context, attrs);    rectPaint = new Paint();    rectPaint.setAntiAlias(true);    rectPaint.setStyle(Style.FILL);    dividerPaint = new Paint();    dividerPaint.setAntiAlias(true);    dividerPaint.setStrokeWidth(dividerWidth);    if (locale == null) {        locale = getResources().getConfiguration().locale;    }}

2)通过setViewPager()这个方法将控件与ViewPager联系起来

public void setViewPager(ViewPager pager) {    this.pager = pager;    if (pager.getAdapter() == null) {        throw new IllegalStateException("ViewPager does not have adapter instance.");    }    pager.addOnPageChangeListener(pageListener);    notifyDataSetChanged();}public void notifyDataSetChanged() {    //先移除掉所有的View ,防止重复添加    tabsContainer.removeAllViews();    tabCount = pager.getAdapter().getCount();    for (int i = 0; i < tabCount; i++) {        //区分是文字还是Icon的导航        if (pager.getAdapter() instanceof IconTabProvider) {            addIconTab(i, ((IconTabProvider) pager.getAdapter()).getPageIconResId(i));        } else {            addTextTab(i, pager.getAdapter().getPageTitle(i).toString());        }    }    updateTabStyles();    //监听视图树,在绘制完毕后调用相关的方法完成初始化工作    getViewTreeObserver().addOnGlobalLayoutListener(new OnGlobalLayoutListener() {        @SuppressWarnings("deprecation")        @SuppressLint("NewApi")        @Override        public void onGlobalLayout() {            if (Build.VERSION.SDK_INT < Build.VERSION_CODES.JELLY_BEAN) {                getViewTreeObserver().removeGlobalOnLayoutListener(this);            } else {                getViewTreeObserver().removeOnGlobalLayoutListener(this);            }            currentPosition = pager.getCurrentItem();            scrollToChild(currentPosition, 0);        }    });}

3)在 onDraw里面根据不同的 Mode绘制不同的下划线样式

@Overrideprotected void onDraw(Canvas canvas) {    super.onDraw(canvas);    if (isInEditMode() || tabCount == 0) {        return;    }    final int height = getHeight();    // draw indicator line    rectPaint.setColor(indicatorColor);    // default: line below current tab    View currentTab = tabsContainer.getChildAt(currentPosition);    float lineLeft = currentTab.getLeft();    float lineRight = currentTab.getRight();    // if there is an offset, start interpolating left and right coordinates between current    // and next tab    if (currentPositionOffset > 0f && currentPosition < tabCount - 1) {        View nextTab = tabsContainer.getChildAt(currentPosition + 1);        final float nextTabLeft = nextTab.getLeft();        final float nextTabRight = nextTab.getRight();        lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset) *                lineLeft);        lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset) *                lineRight);    }    canvas.drawRect(lineLeft, height - indicatorHeight, lineRight, height, rectPaint);    // draw underline    rectPaint.setColor(underlineColor);    canvas.drawRect(0, height - underlineHeight, tabsContainer.getWidth(), height, rectPaint);    // draw divider    dividerPaint.setColor(dividerColor);    for (int i = 0; i < tabCount - 1; i++) {        View tab = tabsContainer.getChildAt(i);        if (!isSame) {            canvas.drawLine(tab.getRight(), dividerPadding, tab.getRight(),                    height - dividerPadding, dividerPaint);        } else {            canvas.drawLine(tab.getRight() + horizontalPadding, dividerPadding,                    tab.getRight() + horizontalPadding, height - dividerPadding, dividerPaint);        }    }}

4)在ViewPager滑动的时候,会调用相应的方法来刷新界面,因为前面我们在setViewPager的时候为其添加pageListener监听器

 public void setViewPager(ViewPager pager) {   //省略了若干方法     pager.addOnPageChangeListener(pageListener);}private class PageListener implements OnPageChangeListener {    @Override    public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {        currentPosition = position;        currentPositionOffset = positionOffset;        View child = tabsContainer.getChildAt(position);        int width = child.getWidth();        if (isSame) {            width += horizontalPadding * 2;        }        Log.i(TAG, "onPageScrolled:width=" + width);        //  调用这个方法是HorizontalScrollView滑动到相应的位置        scrollToChild(position, (int) (positionOffset * width));        //调用这个方法重新绘制        invalidate();        if (delegatePageListener != null) {            delegatePageListener.onPageScrolled(position, positionOffset, positionOffsetPixels);        }    }    @Override    public void onPageScrollStateChanged(int state) {        if (delegatePageListener != null) {            delegatePageListener.onPageScrollStateChanged(state);        }    }    @Override    public void onPageSelected(int position) {        if (delegatePageListener != null) {            delegatePageListener.onPageSelected(position);        }    }}

源码到此分析为止

题外话

1)大家在使用过程实现由什么缺陷的,希望大家能够及时告知,同时大家有空的话也可以到我的github上面start或者fork,谢谢,你们的支持就是我的最大动力

2)在接下来的日子我会尝试封装好多种效果,不过估计得忙过这阵子,因为最近在准备校招,有时候看那些算法题目,感觉世界都没爱了,哈哈,放松一下,大家有什么好的面试经验也来分享一下

源码参考项目:PagerSlidingTabStrip

我的简书主页

转载请注明原博客地址:

Github例子源码下载地址:https://github.com/gdutxiaoxu/ViewPagerTabIndicator.git

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