Android 设置DrawableRight和DrawableLeft点击事件

Android的TextView有个DrawableLeft和DrawableRight属性，UI布局中经常会用到。比如登陆界面，用户名和密码前面的图像，就是用DrawableLeft来设置的。

但比较郁闷的是，android并没有为DrawableLeft和DrawableRight提供监听点击事件的api，但这个需求是很常见的，比如输入密码的时候，点击右边的眼睛，密码变为明文。

其实思路很简单，我们只要重写EditText的onTouchEvent，捕捉到点击事件，然后判断用户点击的位置是否点击到图标即可，不废话，用代码说话。

1、添加XTextView类继承自TextView

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;

public class XTextView extends android.support.v7.widget.AppCompatTextView {
    private DrawableLeftListener mLeftListener;
    private DrawableRightListener mRightListener;

    final int DRAWABLE_LEFT = 0;
    final int DRAWABLE_TOP = 1;
    final int DRAWABLE_RIGHT = 2;
    final int DRAWABLE_BOTTOM = 3;

    public XTextView(Context context) {
        super(context);
    }

    public XTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

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

    public void setDrawableLeftListener(DrawableLeftListener listener) {
        this.mLeftListener = listener;
    }

    public void setDrawableRightListener(DrawableRightListener listener) {
        this.mRightListener = listener;
    }

    public interface DrawableLeftListener {
        public void onDrawableLeftClick(View view);
    }

    public interface DrawableRightListener {
        public void onDrawableRightClick(View view);
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_DOWN:
                if (mRightListener != null) {
                    Drawable drawableRight = getCompoundDrawables()[DRAWABLE_RIGHT];
                    if (drawableRight != null && event.getRawX() >= (getRight() - drawableRight.getBounds().width())) {
                        mRightListener.onDrawableRightClick(this);
                        return true;
                    }
                }
                if (mLeftListener != null) {
                    Drawable drawableLeft = getCompoundDrawables()[DRAWABLE_LEFT];
                    if (drawableLeft != null && event.getRawX() <= (getLeft() + drawableLeft.getBounds().width()))
                        mLeftListener.onDrawableLeftClick(this);
                    return true;
                }
                break;
        }
        return super.onTouchEvent(event);
    }
}

2、layout

3、activity添加点击响应

xtvLoginBack.setDrawableLeftListener(new XTextView.DrawableLeftListener() {
    @Override
    public void onDrawableLeftClick(View view) {
        onBackPressed();
    }
});

参考：

http://blog.csdn.net/tom_xiaoxie/article/details/50771763