OnKeyDown方法

该方法是接口KeyEvent.Callback中的抽象方法。所有的View全部实现了该接口并重写了该方法。该方法是用来捕捉手机键盘被按下的事件。

其mainActivity.java的代码如下：

package com.example.onkeydown;


import java.security.PublicKey;


import android.R.integer;
import android.app.Activity;
import android.content.Context;
import android.os.Bundle;
import android.util.Log;
import android.view.KeyEvent;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;




public class MainActivity extends Activity {

MyButton myButton;
public final String TAG="MainActivity";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        myButton=new MyButton(this);
        myButton.setText("全屏按钮");
        myButton.setTextSize(30);
        setContentView(myButton);
    }
    public boolean onKeyDown(int KeyCode,KeyEvent event){
    Log.d(TAG, "activity onKeyDown");
    return super.onKeyDown(KeyCode, event);
    }
   class MyButton extends Button{
  public MyButton(Context context){
  super(context);
  }
  public boolean onKeyDown(int KeyCode,KeyEvent event){
  Log.d(TAG, "MyView onKeyDown");
  return false;
  }
   }


    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.main, menu);
        return true;
    }


    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();
        if (id == R.id.action_settings) {
            return true;
        }
        return super.onOptionsItemSelected(item);
    }
}