//这个是View的一个回调接口
/**
* Interface definition for a callback to be invoked when a view is clicked.
*/
public interface OnClickListener {
    /**
     * Called when a view has been clicked.
     *
     * @param v The view that was clicked.
     */
    void onClick(View v);
}  import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity implements OnClickListener{
     private Button button;
     @Override
     public void onCreate(Bundle savedInstanceState) {
          super.onCreate(savedInstanceState);
          setContentView(R.layout.activity_main);
          button = (Button)findViewById(R.id.button1);
          
        
          button.setOnClickListener(this);
     }
     @Override
     public void onClick(View v) {
          Toast.makeText(getApplication(), "OnClick", Toast.LENGTH_LONG).show();
     }
}
    这就是一个很典型的例子,当然也可以这样写:
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
public class SSSS extends Activity {
     private Button button;
     private OnClickListener clickListener = new OnClickListener() {
          @Override
          public void onClick(View v) {
               // TODO Auto-generated method stub
          }
     };
     @Override
     protected void onCreate(Bundle savedInstanceState) {
          // TODO Auto-generated method stub
          super.onCreate(savedInstanceState);
          button = (Button)findViewById(R.id.button1);
          button.setOnClickListener(clickListener);  
     }
}
  /**
*
*/
public class View implements Drawable.Callback, KeyEvent.Callback, AccessibilityEventSource {
     /**
     * Listener used to dispatch click events.
     * This field should be made private, so it is hidden from the SDK.
     * {@hide}
     */
    protected OnClickListener mOnClickListener;
   
    /**
     *
     * Register a callback to be invoked when this view is clicked. If this view is not
     * clickable, it becomes clickable.
     *
     * @param l The callback that will run
     *
     * @see #setClickable(boolean)
     */
   
    public void setOnClickListener(OnClickListener l) {
        if (!isClickable()) {
            setClickable(true);
        }
        mOnClickListener = l;
    }
   
   
    /**
     * Call this view‘s OnClickListener, if it is defined.
     *
     * @return True there was an assigned OnClickListener that was called, false
     *         otherwise is returned.
     */
    public boolean performClick() {
        sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_CLICKED);
        if (mOnClickListener != null) {
            playSoundEffect(SoundEffectConstants.CLICK);
           
            mOnClickListener.onClick(this);
            return true;
        }
        return false;
    }
} final Dialog dialog = new Dialog(this, R.style.MyDialogStyle);
          dialog.setContentView(R.layout.dialog_exit_train);
          dialog.show();
          ImageButton ib_affirm = (ImageButton) dialog
                    .findViewById(R.id.dialog_exit_ib_affirm);
          ImageButton ib_cancel = (ImageButton) dialog
                    .findViewById(R.id.dialog_exit_ib_cancel);
          ib_affirm.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View v) {
                    saveUserData();
                    dialog.dismiss();
                    TestActivity.this.finish();
               }
          });
          ib_cancel.setOnClickListener(new View.OnClickListener() {
               @Override
               public void onClick(View v) {
                    dialog.dismiss();
               }
          });  import android.app.Dialog;
import android.content.Context;
import android.os.Bundle;
import android.text.TextPaint;
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.widget.Button;
import android.widget.TextView;
import com.fanfou.app.opensource.R;
/**
* 
*
*/
public class AlertInfoDialog extends Dialog implements View.OnClickListener {
    //创建接口
    public static interface OnOKClickListener {
        public void onOKClick();
    }
    private final Context mContext;
    private TextView mTitleView;
    private TextView mTextView;
    private Button mButtonOk;
    private CharSequence mTitle;
    private CharSequence mText;
    //生命接口对象
    private OnOKClickListener mClickListener;
    public AlertInfoDialog(final Context context, final String title,
            final String text) {
        super(context, R.style.Dialog);
        this.mContext = context;
        this.mTitle = title;
        this.mText = text;
    }
    private void init() {
        setContentView(R.layout.dialog_alert);
        this.mTitleView = (TextView) findViewById(R.id.title);
        final TextPaint tp = this.mTitleView.getPaint();
        tp.setFakeBoldText(true);
        this.mTitleView.setText(this.mTitle);
        this.mTextView = (TextView) findViewById(R.id.text);
        this.mTextView.setText(this.mText);
        this.mButtonOk = (Button) findViewById(R.id.button_ok);
        this.mButtonOk.setOnClickListener(this);
    }
    @Override
    public void onClick(final View v) {
        final int id = v.getId();
        switch (id) {
        case R.id.button_ok:
            cancel();//调用
            if (this.mClickListener != null) {
                this.mClickListener.onOKClick();
            }
            break;
        default:
            break;
        }
    }
    @Override
    protected void onCreate(final Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setBlurEffect();
        init();
    }
    protected void setBlurEffect() {
        final Window window = getWindow();
        final WindowManager.LayoutParams lp = window.getAttributes();
        // lp.alpha=0.8f;
        lp.dimAmount = 0.6f;
        window.setAttributes(lp);
        window.addFlags(WindowManager.LayoutParams.FLAG_DIM_BEHIND);
        // window.addFlags(WindowManager.LayoutParams.FLAG_BLUR_BEHIND);
    }
    public void setMessage(final CharSequence message) {
        this.mText = message;
        this.mTextView.setText(this.mText);
    }
    public void setMessage(final int resId) {
        this.mText = this.mContext.getResources().getText(resId);
        this.mTextView.setText(this.mText);
    }
    //设置监听器 也就是实例化接口
    public void setOnClickListener(final OnOKClickListener clickListener) {
        this.mClickListener = clickListener;
    }
    @Override
    public void setTitle(final CharSequence title) {
        this.mTitle = title;
        this.mTitleView.setText(this.mTitle);
    }
    @Override
    public void setTitle(final int resId) {
        this.mTitle = this.mContext.getResources().getText(resId);
        this.mTitleView.setText(this.mTitle);
    }
}原文:http://blog.csdn.net/wangjinyu501/article/details/22052187