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在广播接收器响应之前获取电池电量意图.行动\u电池\u更换

battery broadcastreceiver android

stealthcopter · 技术社区 · 16 年前

private BroadcastReceiver mBatInfoReceiver = new BroadcastReceiver(){
    @Override
    public void onReceive(Context arg0, Intent intent) {
        int level = intent.getIntExtra("level", 0);
        // do something...
    }
}

    registerReceiver(this.mBatInfoReceiver, 
            new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

但是,此代码必须等待电池状态更新,因此如果需要根据电池级别设置GUI元素,则必须等待电池事件发生。有没有办法轻推它让它工作或只是运行一些代码,看看电池水平是什么在最后一次广播?

6 回复 | 直到 16 年前

Community Mohan Dere 9 年前

有没有一种方法来推动它工作或只是运行一些代码,看看电池的水平是什么最后一次广播?

registerReceiver() 用你的 IntentFilter 和一个 null BroadcastReceiver 最后一次广播 Intent . 这是因为 ACTION_BATTERY_CHANGED 是一种所谓的“粘性广播”,我更详细地描述了一下 this StackOverflow question-and-answer .

ThomasW 9 年前

这是在不注册接收器的情况下获取电池电量的方法:

Intent batteryIntent = context.getApplicationContext().registerReceiver(null,
                    new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
int rawlevel = batteryIntent.getIntExtra(BatteryManager.EXTRA_LEVEL, -1);
double scale = batteryIntent.getIntExtra(BatteryManager.EXTRA_SCALE, -1);
double level = -1;
if (rawlevel >= 0 && scale > 0) {
    level = rawlevel / scale;
}

由于广播的粘性,它可以使用空广播接收器。

它使用getApplicationContext()技巧,以防您在intent接收器中遇到异常:

android.content.ReceiverCallNotAllowedException异常: 允许注册接收意图

XXX 12 年前

    public static String batteryLevel(Context context)
    {
        Intent intent  = context.registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));   
        int    level   = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
        int    scale   = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 100);
        int    percent = (level*100)/scale;
        return String.valueOf(percent) + "%";
    }

Hiren Patel 13 年前

// Put this Code into your MainActivity

private BroadcastReceiver mBatInfoReceiver = new BroadcastReceiver() {
    @Override
    public void onReceive(Context c, Intent i) {
        int level = i.getIntExtra("level", 0);
        ProgressBar pb = (ProgressBar) findViewById(R.id.progressbar);
        pb.setProgress(level);
        TextView tv = (TextView) findViewById(R.id.textfield);
        tv.setText("Battery Level: " + Integer.toString(level) + "%");
    }

};

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    registerReceiver(mBatInfoReceiver, new IntentFilter(
            Intent.ACTION_BATTERY_CHANGED));
}

Jorgesys 12 年前

我使用此方法获取电池电量,而不接收更新。

public float getMyBatteryLevel() {
        Intent batteryIntent = this.getApplicationContext().registerReceiver(null,
        new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
        return batteryIntent.getIntExtra("level", -1);
}

Johan 10 年前

请注意,您从registerReceiver call获得的意图

Intent intent  = context.registerReceiver(null, new IntentFilter(Intent.ACTION_BATTERY_CHANGED));

if(intent != null){ 
// do your stuff here... 
}

我刚得到一个空指针异常,导致应用程序崩溃!