获取手机电池的剩余电量

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。

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();
};
}

系统获取电池方法以及根据电量改变指示灯的颜色，在BatteryService类中修改

final int level = mBatteryProps.batteryLevel;

final int status = mBatteryProps.batteryStatus;

final int batteryLowLedOn = 1000;
final int batteryLowLedOff = 3000;

if (level <= 20) {
try {
if (mLight != null)
mLightsService.close(mLight.getType());
} catch (Exception e) {
e.printStackTrace();
}
if (status == BatteryManager.BATTERY_STATUS_CHARGING) {
// Solid red when battery is charging
// mBatteryLight.setColor(mBatteryLowARGB);
mLight = new com.android.internal.policy.Light(Light.CHARGING, 3000, 5000, mBatteryLowARGB);
} else {
// Flash red when battery is low and not charging
// mBatteryLight.setFlashing(mBatteryLowARGB,
// LightsService.LIGHT_FLASH_TIMED,
// batteryLowLedOn, batteryLowLedOff);
mLight = new com.android.internal.policy.Light(Light.LOW_BATTERY, batteryLowLedOn,
batteryLowLedOff, mBatteryLowARGB);
}
try {
mLightsService.open(mLight);
} catch (Exception e) {
e.printStackTrace();
}
} else {
// mBatteryLight.turnOff();
try {
if (mLight != null)
mLightsService.close(mLight.getType());
else
mLightsService.close(com.android.internal.policy.Light.POWER_ALL); //i dont have time to test,set this to avoid the light not off
} catch (Exception e) {
e.printStackTrace();
}
if (level < 90) {
mLight = new com.android.internal.policy.Light(Light.CHARGING, 3000, 5000, mBatteryMediumARGB);
}else if(level >= 90){
mLight = new com.android.internal.policy.Light(Light.CHARGE_COMPLETE,3000, 5000,mBatteryFullARGB);
}else if (status == BatteryManager.BATTERY_STATUS_FULL){
// mBatteryLight.setColor(mBatteryFullARGB);
mLight = new com.android.internal.policy.Light(Light.CHARGE_COMPLETE, 0, 0, mBatteryFullARGB);
}
try {
mLightsService.open(mLight);
} catch (Exception e) {
e.printStackTrace();
}
}