Android 带清除功能的输入框控件实例详解

package com.example.clearedittext;  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.View.OnFocusChangeListener; import android.view.animation.Animation; import android.view.animation.CycleInterpolator; import android.view.animation.TranslateAnimation; import android.widget.EditText;  public class ClearEditText extends EditText implements      OnFocusChangeListener, TextWatcher {    /**    * 删除按钮的引用    */   private Drawable mClearDrawable;    /**    * 控件是否有焦点    */   private boolean hasFoucs;     public ClearEditText(Context context) {      this(context, null);    }      public ClearEditText(Context context, AttributeSet attrs) {      //这里构造方法也很重要，不加这个很多属性不能再XML里面定义     this(context, attrs, android.R.attr.editTextStyle);    }       public ClearEditText(Context context, AttributeSet attrs, int defStyle) {     super(context, attrs, defStyle);     init();   }         private void init() {      //获取EditText的DrawableRight,假如没有设置我们就使用默认的图片     mClearDrawable = getCompoundDrawables()[2];      if (mClearDrawable == null) {  //     throw new NullPointerException("You can add drawableRight attribute in XML");       mClearDrawable = getResources().getDrawable(R.drawable.delete_selector);      }           mClearDrawable.setBounds(0, 0, mClearDrawable.getIntrinsicWidth(), mClearDrawable.getIntrinsicHeight());      //默认设置隐藏图标     setClearIconVisible(false);      //设置焦点改变的监听     setOnFocusChangeListener(this);      //设置输入框里面内容发生改变的监听     addTextChangedListener(this);    }        /**    * 因为我们不能直接给EditText设置点击事件，所以我们用记住我们按下的位置来模拟点击事件    * 当我们按下的位置 在 EditText的宽度 - 图标到控件右边的间距 - 图标的宽度 和    * EditText的宽度 - 图标到控件右边的间距之间我们就算点击了图标，竖直方向就没有考虑    */   @Override    public boolean onTouchEvent(MotionEvent event) {     if (event.getAction() == MotionEvent.ACTION_UP) {       if (getCompoundDrawables()[2] != null) {          boolean touchable = event.getX() > (getWidth() - getTotalPaddingRight())             && (event.getX() < ((getWidth() - getPaddingRight())));                  if (touchable) {           this.setText("");         }       }     }      return super.onTouchEvent(event);   }     /**    * 当ClearEditText焦点发生变化的时候，判断里面字符串长度设置清除图标的显示与隐藏    */   @Override    public void onFocusChange(View v, boolean hasFocus) {      this.hasFoucs = hasFocus;     if (hasFocus) {        setClearIconVisible(getText().length() > 0);      } else {        setClearIconVisible(false);      }    }        /**    * 设置清除图标的显示与隐藏，调用setCompoundDrawables为EditText绘制上去    * @param visible    */   protected void setClearIconVisible(boolean visible) {      Drawable right = visible ? mClearDrawable : null;      setCompoundDrawables(getCompoundDrawables()[0],          getCompoundDrawables()[1], right, getCompoundDrawables()[3]);    }           /**    * 当输入框里面内容发生变化的时候回调的方法    */   @Override    public void onTextChanged(CharSequence s, int start, int count,        int after) {          if(hasFoucs){           setClearIconVisible(s.length() > 0);         }   }      @Override    public void beforeTextChanged(CharSequence s, int start, int count,        int after) {          }      @Override    public void afterTextChanged(Editable s) {          }          /**    * 设置晃动动画    */   public void setShakeAnimation(){     this.setAnimation(shakeAnimation(5));   }         /**    * 晃动动画    * @param counts 1秒钟晃动多少下    * @return    */   public static Animation shakeAnimation(int counts){     Animation translateAnimation = new TranslateAnimation(0, 10, 0, 0);     translateAnimation.setInterpolator(new CycleInterpolator(counts));     translateAnimation.setDuration(1000);     return translateAnimation;   }     }