在Android EditText控件中，我们如何自定义带有清空删除按钮的EditText控件呢？非常的简单，我们只需要创建一个CleanableEditText类，继承于EditText即可，代码如下：

package com.tpyyes.shouxie;

import android.content.Context;
import android.graphics.drawable.Drawable;
import android.text.Editable;
import android.text.TextWatcher;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.View;
import android.view.animation.Animation;
import android.view.animation.CycleInterpolator;
import android.view.animation.TranslateAnimation;
import android.widget.EditText;
/**
 * 在焦点变化时和输入内容发生变化时均要判断是否显示右边clean图标
 */
public class CleanableEditText extends EditText {
    private Drawable mRightDrawable;
    private boolean isHasFocus;
    private CustomDeletedCallback customDeletedCallback;

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

    public CleanableEditText(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        init();
    }

    private void init(){
        //getCompoundDrawables:
        //Returns drawables for the left, top, right, and bottom borders.
        Drawable [] drawables=this.getCompoundDrawables();

        //取得right位置的Drawable
        //即我们在布局文件中设置的android:drawableRight
        mRightDrawable=drawables[2];

        //设置焦点变化的监听
        this.setOnFocusChangeListener(new FocusChangeListenerImpl());
        //设置EditText文字变化的监听
        this.addTextChangedListener(new TextWatcherImpl());
        //初始化时让右边clean图标不可见
        setClearDrawableVisible(false);
    }


    /**
     * 当手指抬起的位置在clean的图标的区域
     * 我们将此视为进行清除操作
     * getWidth():得到控件的宽度
     * event.getX():抬起时的坐标(改坐标是相对于控件本身而言的)
     * getTotalPaddingRight():clean的图标左边缘至控件右边缘的距离
     * getPaddingRight():clean的图标右边缘至控件右边缘的距离
     * 于是:
     * getWidth() - getTotalPaddingRight()表示:
     * 控件左边到clean的图标左边缘的区域
     * getWidth() - getPaddingRight()表示:
     * 控件左边到clean的图标右边缘的区域
     * 所以这两者之间的区域刚好是clean的图标的区域
     */
    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (event.getAction()) {
            case MotionEvent.ACTION_UP:
                //删除EditText内容
                boolean isClean =(event.getX() > (getWidth() - getTotalPaddingRight()))&&
                        (event.getX() < (getWidth() - getPaddingRight()));
                if (isClean) {
                    setText("");
                    //删除回调
                    customDeletedCallback.onDeleted(this);
                }
                break;

            default:
                break;
        }
        return super.onTouchEvent(event);
    }

    private class FocusChangeListenerImpl implements OnFocusChangeListener{
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            isHasFocus=hasFocus;
            if (isHasFocus) {
                boolean isVisible=getText().toString().length()>=1;
                setClearDrawableVisible(isVisible);
            } else {
                setClearDrawableVisible(false);
            }
        }

    }

    //当输入结束后判断是否显示右边clean的图标
    private class TextWatcherImpl implements TextWatcher{
        @Override
        public void afterTextChanged(Editable s) {
            boolean isVisible=getText().toString().length()>=1;
            setClearDrawableVisible(isVisible);
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,int after) {

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before,int count) {

        }

    }

    //隐藏或者显示右边clean的图标
    protected void setClearDrawableVisible(boolean isVisible) {
        Drawable rightDrawable;
        if (isVisible) {
            rightDrawable = mRightDrawable;
        } else {
            rightDrawable = null;
        }
        //使用代码设置该控件left, top, right, and bottom处的图标
        setCompoundDrawables(getCompoundDrawables()[0],getCompoundDrawables()[1],
                rightDrawable,getCompoundDrawables()[3]);
    }

    // 显示一个动画,以提示用户输入
    public void setShakeAnimation() {
        this.setAnimation(shakeAnimation(5));
    }

    //CycleTimes动画重复的次数
    public Animation shakeAnimation(int CycleTimes) {
        Animation translateAnimation = new TranslateAnimation(0, 10, 0, 10);
        translateAnimation.setInterpolator(new CycleInterpolator(CycleTimes));
        translateAnimation.setDuration(1000);
        return translateAnimation;
    }

    //自定义右侧清空按钮回调事件
    public interface CustomDeletedCallback {
        void onDeleted(CleanableEditText cleanableEditText);
    }
    //自定义删除回调(返回void也行)
    public CleanableEditText setCustomDeletedCallback(CustomDeletedCallback customDeletedCallback) {
        this.customDeletedCallback = customDeletedCallback;
        return this;
    }
}

然后在xml中加入我们自定义的CleanableEditText类的控件，代码如下：

<com.tpyyes.shouxie.CleanableEditText
	android:layout_width="match_parent"
	android:layout_height="80dp"
	android:focusable="true"
	android:focusableInTouchMode="true"
	android:cursorVisible="true"
	android:drawableRight="@drawable/delete_24dp" //右侧删除按钮图标
	android:id="@+id/msgBox"/>

在java类中使用带有自定义删除按钮的CleanableEditText类，代码如下：

CleanableEditText msgBox = findViewById(R.id.msgBox);
msgBox.setCustomDeletedCallback(new CleanableEditText.CustomDeletedCallback() {
	@Override
	public void onDeleted(CleanableEditText cleanableEditText) {
		// do something after delete EditText
	}
});

效果如图所示：