TextView 和 EditText 的 DrawableRight 點擊事件的處理

類似的 EditText 也可以這樣處理，同理其他方向的 drawable。新增了一些自定義屬性可以方便的改變 drawable 的大小。

public class DrawableTextView extends TextView {

    public static final int LEFT = 1, TOP = 2, RIGHT = 3, BOTTOM = 4;
    public DrawableRightClickListener drawableRightClickListener;

    public DrawableTextView(Context context) {
        this(context, null);
    }

    public DrawableTextView(Context context, AttributeSet attrs) {
        this(context, attrs, 0);
    }

    public DrawableTextView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        init(attrs);
    }


    public DrawableRightClickListener getDrawableRightClick() {
        return drawableRightClickListener;
    }

    public void setDrawableRightClick(DrawableRightClickListener drawableRightClickListener) {
        this.drawableRightClickListener = drawableRightClickListener;
    }

    //爲了方便,直接寫了一個內部類的接口
    public interface DrawableRightClickListener {
        void onDrawableRightClickListener(View view);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                if (drawableRightClickListener != null) {
                    Drawable rightDrawable = getCompoundDrawables()[2];
                    //判斷的依據是獲取點擊區域相對於屏幕的x值比我(獲取TextView的最右邊界減去邊界寬度)大就可以判斷點擊在Drawable上
                    if (rightDrawable != null && event.getRawX() >= (getRight() - rightDrawable.getBounds().width() - getPaddingRight())) {
                        drawableRightClickListener.onDrawableRightClickListener(this);
                        return true;
                    }
                }
                break;
        }
        return super.onTouchEvent(event);
    }





    private void init(AttributeSet attrs) {
        if (attrs != null) {
            TypedArray a = getContext().obtainStyledAttributes(attrs, R.styleable.DrawableTextView);
            int mWidth = a
                    .getDimensionPixelSize(R.styleable.DrawableTextView_drawable_width, 0);
            int mHeight = a.getDimensionPixelSize(R.styleable.DrawableTextView_drawable_height,
                    0);
            Drawable mDrawable = a.getDrawable(R.styleable.DrawableTextView_drawable_src);
            int mLocation = a.getInt(R.styleable.DrawableTextView_drawable_location, LEFT);
            a.recycle();
            drawDrawable(mDrawable, mWidth, mHeight, mLocation);
        }
    }

    public void drawDrawable(Drawable mDrawable, int mWidth, int mHeight, int mLocation) {
        if (mDrawable != null) {
            if (mWidth != 0 && mHeight != 0) {
                mDrawable.setBounds(0, 0, mWidth, mHeight);
            }
            switch (mLocation) {
                case LEFT:
                    this.setCompoundDrawables(mDrawable, null,
                            null, null);
                    break;
                case TOP:
                    this.setCompoundDrawables(null, mDrawable,
                            null, null);
                    break;
                case RIGHT:
                    this.setCompoundDrawables(null, null,
                            mDrawable, null);
                    break;
                case BOTTOM:
                    this.setCompoundDrawables(null, null, null,
                            mDrawable);
                    break;
            }
        }
    }
}

//對應的自定義屬性
<!--DrawableTextView-->
    <declare-styleable name="DrawableTextView">
        <attr name="drawable_src" format="reference"/>
        <attr name="drawable_height" format="dimension"/>
        <attr name="drawable_width" format="dimension"/>
        <attr name="drawable_location">
            <enum name="left" value="1"/>
            <enum name="top" value="2"/>
            <enum name="right" value="3"/>
            <enum name="bottom" value="4"/>
        </attr>
    </declare-styleable>