取得手机电池的剩余量

[java]
/*
* 取得手机电池的剩余量
* Android API中的BroadcastReceiver(Android.content.BroadcastReceiver)
* 类有点像Button中的Listener，当Receiver被注册后，会在后台等待其他程序
* 的调用，程序将通过注册BroadcastReceiver时设置的IntentFilter来捕捉系统
* 发出的Intent.ACTION_BATTERY_CHANGED这个action,再以此取得手机电池的剩
* 余量。
*/

import 略;
[java]
public class Ex06_02Activity extends Activity {
    private int intLevel;
    private int intScale;
    private Button mButton01;
    private AlertDialog d;
    // 创建BroadcastReceiver
    private BroadcastReceiver mBatInfoReveiver = new BroadcastReceiver() {

        @Override
        public void onReceive(Context context, Intent intent) {
            // TODO Auto-generated method stub
            String action = intent.getAction();
            // 如果捕捉到action是ACRION_BATTERY_CHANGED
            // 就运行onBatteryInfoReveiver()
            if (intent.ACTION_BATTERY_CHANGED.equals(action)) {
                intLevel = intent.getIntExtra("level", 0);
                intScale = intent.getIntExtra("scale", 100);
                onBatteryInfoReceiver(intLevel, intScale);
            }
        }
    };

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        mButton01 = (Button) findViewById(R.id.myButton1);
        mButton01.setOnClickListener(new OnClickListener() {

            @Override
            public void onClick(View v) {
                // TODO Auto-generated method stub
                // 注册一个BroadcastReceiver，作为访问电池计量之用
                registerReceiver(mBatInfoReveiver, new IntentFilter(
                        Intent.ACTION_BATTERY_CHANGED));
            }
        });
    }

    // 拦截到ACTION_BATTRY_CHANGED后要执行的动作
    private void onBatteryInfoReceiver(int intLevel, int intScale) {
        // TODO Auto-generated method stub
        d = new AlertDialog.Builder(Ex06_02Activity.this).create();
        d.setTitle(R.string.str_dialog_title);
        d.setMessage(getResources().getString(R.string.str_dialog_body)
                + String.valueOf(intLevel * 100 / intScale) + "%");
        d.setButton(getResources().getString(R.string.str_button2),
                new DialogInterface.OnClickListener() {

                    @Override
                    public void onClick(DialogInterface dialog, int which) {
                        // TODO Auto-generated method stub
                        // 取消注册，并关闭对话框
                        unregisterReceiver(mBatInfoReveiver);
                        d.dismiss();
                    }
                });
        d.show();
    };
}

下面我们来看看程序运行后的结果：www.zzzyk.com

在Android API中有提到，要注册Intent.ACTION_BATTERY_CHANGED的Receiver只能在程序中以
Context.register Receiver()方法来注册，而不能直接在AndroidManifest.xml中注册。
作者：Jasonzhou613

补充：移动开发 , Android ,