AndroidUI设计系列之自定义EditText实现带清除功能的输入框(3)

public class ClearEditText extends EditText implements TextWatcher, 
 OnFocusChangeListener { 
 
 /** 
 * 左右两侧图片资源 
 */ 
 private Drawable left, right; 
 /** 
 * 是否获取焦点，默认没有焦点 
 */ 
 private boolean hasFocus = false; 
 /** 
 * 手指抬起时的X坐标 
 */ 
 private int xUp = 0; 
 
 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); 
 initWedgits(); 
 } 
 
 /** 
 * 初始化各组件 
 * @param attrs 
 *  属性集 
 */ 
 private void initWedgits() { 
 try { 
  // 获取drawableLeft图片，如果在布局文件中没有定义drawableLeft属性，则此值为空 
  left = getCompoundDrawables()[0]; 
  // 获取drawableRight图片，如果在布局文件中没有定义drawableRight属性，则此值为空 
  right = getCompoundDrawables()[2]; 
  initDatas(); 
 } catch (Exception e) { 
  e.printStackTrace(); 
 } 
 } 
 
 /** 
 * 初始化数据 
 */ 
 private void initDatas() { 
 try { 
  // 第一次显示，隐藏删除图标 
  setCompoundDrawablesWithIntrinsicBounds(left, null, null, null); 
  addListeners(); 
 } catch (Exception e) { 
  e.printStackTrace(); 
 } 
 } 
 
 /** 
 * 添加事件监听 
 */ 
 private void addListeners() { 
 try { 
  setOnFocusChangeListener(this); 
  addTextChangedListener(this); 
 } catch (Exception e) { 
  e.printStackTrace(); 
 } 
 } 
 
 @Override 
 public void beforeTextChanged(CharSequence s, int start, int count, 
  int after) { 
 } 
 
 @Override 
 public void onTextChanged(CharSequence s, int start, int before, int after) { 
 if (hasFocus) { 
  if (TextUtils.isEmpty(s)) { 
  // 如果为空，则不显示删除图标 
  setCompoundDrawablesWithIntrinsicBounds(left, null, null, null); 
  } else { 
  // 如果非空，则要显示删除图标 
  if (null == right) { 
   right = getCompoundDrawables()[2]; 
  } 
  setCompoundDrawablesWithIntrinsicBounds(left, null, right, null); 
  } 
 } 
 } 
 
 @Override 
 public boolean onTouchEvent(MotionEvent event) { 
 try { 
  switch (event.getAction()) { 
  case MotionEvent.ACTION_UP: 
  // 获取点击时手指抬起的X坐标 
  xUp = (int) event.getX(); 
  // 当点击的坐标到当前输入框右侧的距离小于等于getCompoundPaddingRight()的距离时，则认为是点击了删除图标 
  // getCompoundPaddingRight()的说明：Returns the right padding of the view, plus space for the right Drawable if any. 
  if ((getWidth() - xUp) <= getCompoundPaddingRight()) { 
   if (!TextUtils.isEmpty(getText().toString())) { 
   setText(""); 
   } 
  } 
  break; 
  default: 
  break; 
  } 
 } catch (Exception e) { 
  e.printStackTrace(); 
 } 
 return super.onTouchEvent(event); 
 } 
 
 @Override 
 public void afterTextChanged(Editable s) { 
 } 
 
 @Override 
 public void onFocusChange(View v, boolean hasFocus) { 
 try { 
  this.hasFocus = hasFocus; 
 } catch (Exception e) { 
  e.printStackTrace(); 
 } 
 } 
} 

<&＃63;xml version="1.0" encoding="utf-8"&＃63;> 
 
  
 
  
 
 

public class MainActivity extends Activity { 
 /** Called when the activity is first created. */ 
 @Override 
 public void onCreate(Bundle savedInstanceState) { 
 super.onCreate(savedInstanceState); 
 setContentView(R.layout.main); 
 } 
}