Android实现自定义带删除功能的EditText实例

/** 
 * @说明： 自定义带删除按钮的EditText 
 * 
 */ 
public class ClearEditText extends EditText implements OnFocusChangeListener, 
    TextWatcher { 
  //EditText右侧的删除按钮 
  private Drawable mClearDrawable; 
  private boolean hasFoucs; 
 
  public ClearEditText(Context context) { 
    this(context, null); 
  } 
 
  public ClearEditText(Context context, AttributeSet attrs) { 
    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,获取图片的顺序是左上右下（0,1,2,3,） 
    mClearDrawable = getCompoundDrawables()[2]; 
    if (mClearDrawable == null) { 
      mClearDrawable = getResources().getDrawable( 
          R.drawable.edit_delete); 
    } 
 
    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); 
  } 
     
  /* @说明：isInnerWidth, isInnerHeight为ture，触摸点在删除图标之内，则视为点击了删除图标 
   * event.getX() 获取相对应自身左上角的X坐标 
   * event.getY() 获取相对应自身左上角的Y坐标 
   * getWidth() 获取控件的宽度 
   * getHeight() 获取控件的高度 
   * getTotalPaddingRight() 获取删除图标左边缘到控件右边缘的距离 
   * getPaddingRight() 获取删除图标右边缘到控件右边缘的距离 
   * isInnerWidth: 
   * getWidth() - getTotalPaddingRight() 计算删除图标左边缘到控件左边缘的距离 
   * getWidth() - getPaddingRight() 计算删除图标右边缘到控件左边缘的距离 
   * isInnerHeight: 
   * distance 删除图标顶部边缘到控件顶部边缘的距离 
   * distance + height 删除图标底部边缘到控件顶部边缘的距离 
   */ 
  @Override 
  public boolean onTouchEvent(MotionEvent event) { 
    if (event.getAction() == MotionEvent.ACTION_UP) { 
      if (getCompoundDrawables()[2] != null) { 
        int x = (int)event.getX(); 
        int y = (int)event.getY(); 
        Rect rect = getCompoundDrawables()[2].getBounds(); 
        int height = rect.height(); 
        int distance = (getHeight() - height)/2; 
        boolean isInnerWidth = x > (getWidth() - getTotalPaddingRight()) && x < (getWidth() - getPaddingRight()); 
        boolean isInnerHeight = y > distance && y <(distance + height); 
        if (isInnerWidth && isInnerHeight) { 
          this.setText(""); 
        } 
      } 
    } 
    return super.onTouchEvent(event); 
  } 
 
  /** 
   * 当ClearEditText焦点发生变化的时候， 
   * 输入长度为零，隐藏删除图标，否则，显示删除图标 
   */ 
  @Override 
  public void onFocusChange(View v, boolean hasFocus) { 
    this.hasFoucs = hasFocus; 
    if (hasFocus) { 
      setClearIconVisible(getText().length() > 0); 
    } else { 
      setClearIconVisible(false); 
    } 
  } 
 
  protected void setClearIconVisible(boolean visible) { 
    Drawable right = visible ? mClearDrawable : null; 
    setCompoundDrawables(getCompoundDrawables()[0], 
        getCompoundDrawables()[1], right, getCompoundDrawables()[3]); 
  } 
 
  @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) { 
 
  } 
   
 
}