android – 在事件上显示复合drawable到EditText

在我在Activity中的应用程序中,我想设置EditText,因为我单击里面(焦点)EditText并键入一个键清除按钮应该出现在EditText的右侧,当EditText为空时,清除按钮必须删除.但它没有显示给我..我应该在这里实现哪些事件..？onTouch或onFocusChange或addTextChangedListener以及那里的代码..？以下代码我在活动中完成了……

在活动中：

clear = getResources().getDrawable(R.drawable.round_clear);
     clear.setBounds(0, 0, clear.getIntrinsicWidth(), clear.getIntrinsicHeight());

和事件

@Override
public void onFocusChange(View v, boolean hasFocus) 
{
    switch (v.getId()) 
    {
        case R.id.uIDEditText:
                if(hasFocus && !uIDEditText.getText().toString().isEmpty())
                     uIDEditText.setCompoundDrawables(null, null, clear, null);                 
                else
                     uIDEditText.setCompoundDrawables(null, null, null, null);
            break;

        case R.id.pwdEditText:
                if(hasFocus && !pwdEditText.getText().toString().isEmpty())
                    pwdEditText.setCompoundDrawables(null, null, clear, null);
                else
                    pwdEditText.setCompoundDrawables(null, null, null, null);

            break;          
    }               
}

另一个事件是：

@Override
public boolean onTouch(View v, MotionEvent event) 
{
    switch (v.getId()) 
    {
        case R.id.uIDEditText:
            final int x = (int)event.getX();
            final int y = (int)event.getY();              
            if(event.getAction() == MotionEvent.ACTION_UP && clear!=null) {
                Rect rBounds = clear.getBounds();

                int n1 = v.getRight();
                int n2 = v.getRight()+rBounds.width();
                int n3 = v.getPaddingTop();
                int n4 = v.getHeight()-v.getPaddingBottom();

                if(x>=(n1) && x<=(n2) && y>=n3 && y<=(n4))
                {
                    uIDEditText.setText("");
                    event.setAction(MotionEvent.ACTION_CANCEL);
                }
            }
    break;
       }
     }

我解决了它……创建了以下代码

public class CustomEditText extends EditText {

private Drawable  dRight;
private Rect rBounds;
CustomEditText(Context context,AttributeSet attributeSet){
    super(context,attributeSet);
}
@Override
public void setCompoundDrawables(Drawable left, Drawable top,
        Drawable right, Drawable bottom) {
    /*if (left != null) {
        dLeft = left;
    }*/
    if (right != null) {
        dRight = right;
    }
    super.setCompoundDrawables(left, top, right, bottom);
}

@Override
public void addTextChangedListener(TextWatcher watcher) {       
    super.addTextChangedListener(watcher);      
}

@Override
protected void onTextChanged(CharSequence text, int start,
        int lengthBefore, int lengthAfter) {        
    super.onTextChanged(text, start, lengthBefore, lengthAfter);
    if(this.getText().toString().length()>0)
        this.setCompoundDrawablesWithIntrinsicBounds(null, null, dRight, null);
    else
        this.setCompoundDrawablesWithIntrinsicBounds(null, null, null, null);
}   
@Override
protected void finalize() throws Throwable {
    dRight = null;
    rBounds = null;
    super.finalize();
}
 }

并添加到xml中：

<com.example.screen.CustomEditText
    android:id="@+id/uIDEditText"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"       
    android:drawableRight="@drawable/round_clear"       
    android:textColor="#ffffff" />

在Activity中(edittext ontouch侦听器)：

uIDEditText.setOnTouchListener(new OnTouchListener() {         
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if (event.getAction() != MotionEvent.ACTION_UP)                         
                return false;

            if (event.getX() > uIDEditText.getWidth()  - clear.getIntrinsicWidth()) 
            {
                uIDEditText.setText("");    
                event.setAction(MotionEvent.ACTION_CANCEL);
            }
            return false;   
        }
    });