Android仿ios7TabBar

<p><strong><span style="font-size:18px;"></span></strong></p><h2><strong><span style="font-size:18px;">最开始的时候是考虑用radioGroup来做，不过当时的要求不是这样，中间的切换的是一个斜的线，就改成继承view了</span><span style="font-size:18px;">直接上代码</span></strong></h2>

package com.hxqc.mall.views.autopackage;import android.content.Context;import android.content.res.Resources;import android.content.res.TypedArray;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.RectF;import android.util.AttributeSet;import android.util.TypedValue;import android.view.MotionEvent;import android.view.View;import com.hxqc.mall.R;/** * Author:viosonlee * Date:2015-08-07 * FIXME * Todo 一个tab切换控件 */public class TopBar extends View {    private Paint mPaint;    private float height;    private float width;    private int mColor = Color.parseColor("#F5f5f5");    private int bColor = Color.parseColor("#f23435");    private float textSize = converTextSize(14);    private float radius = converTextSize(8);    private int count = 3;//选项的数目    private String[] texts = null;    private float lineWidth = converTextSize(1);//线条的宽度    private int checkedIndex = 0;//选中的角标    private RectF midleRectF,//当只有一个选项的时候按钮的中间区域            maxRectF, //当大于一个的时候按钮的最大区域            startRoundRectF,//左边的画圆角区域            endRoundRectF, //右边画圆角的区域            startRectF, //当选择在第一项时填充区域            endRectF;//当选择最后一项是填充区域    public void setCheckedIndex(int checkedIndex) {        this.checkedIndex = checkedIndex;        invalidate();    }    public int getCheckedIndex() {        return checkedIndex;    }    public void setTexts(String[] texts) {        this.texts = texts;        invalidate();    }    public void setmColor(int mColor) {        this.mColor = mColor;        invalidate();    }    public void setTextSize(float textSize) {        this.textSize = converTextSize(textSize);        invalidate();    }    public void setRadius(float radius) {        this.radius = converTextSize(radius);        invalidate();    }    private OnSelectListener selectListener;    public TopBar(Context context) {        this(context, null);    }    public TopBar(Context context, AttributeSet attrs) {        this(context, attrs, 0);    }    public TopBar(Context context, AttributeSet attrs, int defStyleAttr) {        super(context, attrs, defStyleAttr);        TypedArray typedArray = context.obtainStyledAttributes(attrs, R.styleable.TopBar);        textSize = typedArray.getDimension(R.styleable.TopBar_textSize, textSize);        mColor = typedArray.getColor(R.styleable.TopBar_selectedBackgroundColor, mColor);        bColor = typedArray.getColor(R.styleable.TopBar_backgroundColor, bColor);        checkedIndex = typedArray.getInteger(R.styleable.TopBar_checkedIndex, checkedIndex);        count = typedArray.getInteger(R.styleable.TopBar_count, count);        float dimension = typedArray.getDimension(R.styleable.TopBar_radius, 8);        radius = converTextSize(dimension);        float dimension1 = typedArray.getDimension(R.styleable.TopBar_lineWidth, 1);        lineWidth = converTextSize(dimension1);        initData(count);        typedArray.recycle();    }    /**     * 初始化数据     *     * @param size     */    private void initData(int size) {        texts = new String[size];        for (int i = 0; i < size; i++) {            String title = "选项" + (i + 1);            texts[i] = title;        }    }    @Override    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {        super.onMeasure(widthMeasureSpec, heightMeasureSpec);        init();    }    /**     * 基本初始化     */    private void init() {        height = getMeasuredHeight();        width = getMeasuredWidth();        mPaint = new Paint();        count = texts.length;        midleRectF = new RectF(width / 3 - lineWidth, lineWidth, width * 2 / 3 - lineWidth, height - lineWidth);//当前为一个的时候        maxRectF = new RectF(lineWidth, lineWidth, width - lineWidth, height - lineWidth);        startRoundRectF = new RectF(lineWidth, lineWidth, 2 * radius - lineWidth, height - lineWidth);        endRoundRectF = new RectF(width - 2 * radius + lineWidth, lineWidth, width - lineWidth, height - lineWidth);        startRectF = new RectF(radius + lineWidth, lineWidth, width / count, height - lineWidth);        endRectF = new RectF(width - width / count, lineWidth, width - radius - lineWidth, height - lineWidth);    }    @Override    public void invalidate() {        super.invalidate();        init();    }    @Override    protected void onDraw(Canvas canvas) {        if (count == 0||checkedIndex > count)            return;//        if (checkedIndex > count) {//            throw new IndexOutOfBoundsException();//        }        float itemWidth = width / count;//每一个的宽度        mPaint.setStyle(Paint.Style.STROKE);        canvas.drawColor(Color.TRANSPARENT);        mPaint.setAntiAlias(true);        mPaint.setColor(mColor);        mPaint.setStrokeWidth(lineWidth);        //只有一个选项的时候        if (count == 1) {            mPaint.setStyle(Paint.Style.FILL);            canvas.drawRoundRect(midleRectF, radius, radius, mPaint);            drawTextColor(canvas, mPaint, bColor, 0);            return;        }        //大于一个选项的时候        canvas.drawRoundRect(maxRectF, radius, radius, mPaint);        for (int i = 0; i < count; i++) {            if (i == checkedIndex) {                //话选中状态                if (i == 0) {                    //选中最左边的时候                    mPaint.setStyle(Paint.Style.FILL);                    canvas.drawRoundRect(startRoundRectF, radius, radius, mPaint);                    canvas.drawRect(startRectF, mPaint);                } else if (i == count - 1) {//                    选中最右边的时候                    mPaint.setStyle(Paint.Style.FILL);                    canvas.drawRoundRect(endRoundRectF, radius, radius, mPaint);                    canvas.drawRect(endRectF, mPaint);                } else {//                    选中其他的地方                    mPaint.setStyle(Paint.Style.FILL);                    canvas.drawRect(i * itemWidth + lineWidth, lineWidth,                            i * itemWidth + itemWidth + lineWidth, height - lineWidth, mPaint);                }//                写字                drawTextColor(canvas, mPaint, bColor, i);            } else {//                写字（非选中状态的）                drawTextColor(canvas, mPaint, mColor, i);            }            if (i != 0 && i != checkedIndex)                canvas.drawLine(i * itemWidth, height - lineWidth, i * itemWidth, lineWidth, mPaint);        }    }    public void setOnSelectListener(OnSelectListener selectListener) {        this.selectListener = selectListener;    }    /**     * 写字     *     * @param canvas     * @param paint     * @param color     * @param position     */    private void drawTextColor(Canvas canvas, Paint paint, int color, int position) {        paint.setTextSize(textSize);        paint.setStyle(Paint.Style.FILL);        String text = getText(position);        float wordWidth = paint.measureText(text);        float v = width / count;        float v0 = v / 2 - wordWidth / 2;//文字的margin        float v1 = height / 2 + textSize / 2 - converTextSize(1.6f);        paint.setColor(color);        canvas.drawText(text, v0 + position * v, v1, paint);    }    /**     * 字符长度设置     *     * @param position     * @return     */    private String getText(int position) {        if (texts[position].length() <= 5)            return texts[position];        else {            String substring = texts[position].substring(0, 5);            return substring + "...";        }    }    @Override    public boolean onTouchEvent(MotionEvent event) {        if (event.getAction() == MotionEvent.ACTION_DOWN) {            float x = event.getX();            int i = (int) (x / width * count);            setCheckedIndex(i);            if (selectListener != null)                selectListener.onSelect(this, i);        }        return true;    }    /**     * 将sp转化为像素     *     * @param textSize     * @return     */    private float converTextSize(float textSize) {        Context c = getContext();        Resources r;        if (c == null)            r = Resources.getSystem();        else            r = c.getResources();        float size = TypedValue.applyDimension(                TypedValue.COMPLEX_UNIT_SP, textSize, r.getDisplayMetrics());        return size;    }    public interface OnSelectListener {        void onSelect(View view, int position);    }}