Android自定義View—帶有刪除按鈕的EditText

MainActivity如下:

package cc.textview5;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
import android.app.Activity;
/**
 * Demo描述:
 * 自定義控件實現帶清除功能的EditText
 * 
 * 學習資料:
 * http://blog.csdn.net/xiaanming/article/details/11066685
 * 
 * Thank you very much
 */
public class MainActivity extends Activity {
    private CleanableEditText mUserNameCleanableEditText;
    private CleanableEditText mPassWordCleanableEditText;
    private Button mLoginButton;
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.main);
		init();
	}
	
	private void init(){
		mUserNameCleanableEditText=(CleanableEditText) findViewById(R.id.userNameEditText);
		mPassWordCleanableEditText=(CleanableEditText) findViewById(R.id.passwordEditText);
		mLoginButton=(Button) findViewById(R.id.loginButton);
		mLoginButton.setOnClickListener(new OnClickListenerImpl());
	}
    
	private class OnClickListenerImpl implements OnClickListener {
		@Override
		public void onClick(View view) {
			if (TextUtils.isEmpty(mUserNameCleanableEditText.getText())) {
				mUserNameCleanableEditText.setShakeAnimation();
				Toast.makeText(MainActivity.this, "請輸入用戶名", Toast.LENGTH_SHORT).show();
			}

			if (TextUtils.isEmpty(mPassWordCleanableEditText.getText())) {
				mPassWordCleanableEditText.setShakeAnimation();
				Toast.makeText(MainActivity.this, "請輸入密碼", Toast.LENGTH_SHORT).show();
			}
		}

	}
	

}

CleanableEditText如下:

package cc.textview5;

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;
/**
 * 在焦點變化時和輸入內容發生變化時均要判斷是否顯示右邊clean圖標
 */
public class CleanableEditText extends EditText {
    private Drawable mRightDrawable;
    private boolean isHasFocus;
	
	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
		//即我們在布局文件中設置的android:drawableRight
        mRightDrawable=drawables[2];	
	   
        //設置焦點變化的監聽
        this.setOnFocusChangeListener(new FocusChangeListenerImpl());
        //設置EditText文字變化的監聽
        this.addTextChangedListener(new TextWatcherImpl());
        //初始化時讓右邊clean圖標不可見
        setClearDrawableVisible(false);
	}
	
	
	/**
	 * 當手指抬起的位置在clean的圖標的區域
	 * 我們將此視為進行清除操作
	 * getWidth():得到控件的寬度
	 * event.getX():抬起時的坐標(改坐標是相對於控件本身而言的)
	 * getTotalPaddingRight():clean的圖標左邊緣至控件右邊緣的距離
	 * getPaddingRight():clean的圖標右邊緣至控件右邊緣的距離
	 * 於是:
	 * getWidth() - getTotalPaddingRight()表示:
	 * 控件左邊到clean的圖標左邊緣的區域
	 * getWidth() - getPaddingRight()表示:
	 * 控件左邊到clean的圖標右邊緣的區域
	 * 所以這兩者之間的區域剛好是clean的圖標的區域
	 */
	@Override
	public boolean onTouchEvent(MotionEvent event) {
		switch (event.getAction()) {
		case MotionEvent.ACTION_UP:
			
			boolean isClean =(event.getX() > (getWidth() - getTotalPaddingRight()))&&
					         (event.getX() < (getWidth() - getPaddingRight()));
			if (isClean) {
				setText("");
			}
			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);
			}
		}
		
	}
	
	//當輸入結束後判斷是否顯示右邊clean的圖標
    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) {
			
		}
    	
    }	
    
    //隱藏或者顯示右邊clean的圖標
	protected void setClearDrawableVisible(boolean isVisible) {
		Drawable rightDrawable;
		if (isVisible) {
			rightDrawable = mRightDrawable;
		} else {
			rightDrawable = null;
		}
		//使用代碼設置該控件left, top, right, and bottom處的圖標
		setCompoundDrawables(getCompoundDrawables()[0],getCompoundDrawables()[1], 
				             rightDrawable,getCompoundDrawables()[3]);
	} 

	// 顯示一個動畫,以提示用戶輸入
	public void setShakeAnimation() {
		this.setAnimation(shakeAnimation(5));
	}

	//CycleTimes動畫重復的次數
	public Animation shakeAnimation(int CycleTimes) {
		Animation translateAnimation = new TranslateAnimation(0, 10, 0, 10);
		translateAnimation.setInterpolator(new CycleInterpolator(CycleTimes));
		translateAnimation.setDuration(1000);
		return translateAnimation;
	}

}

main.xml如下: