Android实时获取电量

转载自：http://blog.csdn.net/chrp99/article/details/9137349

public class MainActivity extends Activity {

class BtteryReceiver extends BroadcastReceiver {  

    @Override  
    public void onReceive(Context context, Intent intent) {  
        // TODO Auto-generated method stub  
        System.out.println("+++++++++++++++++++++++");  
        // 判断它是否是为电量变化的Broadcast Action  
        if (Intent.ACTION_BATTERY_CHANGED.equals(intent.getAction())) {  
            // 获取当前电量  
            int level = intent.getIntExtra("level", 0);  
            // 电量的总刻度  
            int scale = intent.getIntExtra("scale", 0);  

            // 把它转换成百分比  
            String content = ("电池电量为" + ((level * 100) / scale) + "%");  

            int key = ((level * 100) / scale);  
            switch (key) {  
            case 100:  
                Toast.makeText(context, "电池已经充满", Toast.LENGTH_LONG).show();  
                break;  
            case 50:  
                Toast.makeText(context, "电池已经使用一半", Toast.LENGTH_LONG)  
                        .show();  
                break;  
            case 30:  
                Toast.makeText(context, "电池已到30%了", Toast.LENGTH_LONG)  
                        .show();  
                break;  
            case 40:  
                Toast.makeText(context, "电池已到31%了", Toast.LENGTH_LONG)  
                        .show();  
                break;  
            case 10:  
                Toast.makeText(context, "电池不足10%", Toast.LENGTH_LONG)  
                        .show();  
                break;  
            case 9:  
                Toast.makeText(context, "电池不足9%", Toast.LENGTH_LONG).show();  
                break;  
            case 5:  
                Toast.makeText(context, "电池不足5%", Toast.LENGTH_LONG).show();  
                break;  

            }  

        }  
    }  

}  

另一篇博客

Android开发者可以利用BroadcastReceiver机制，获取电池电量变化的ACTION_BATTERY_CHANGED intent，进而获取当前android设备的电池状态。
具体操作步骤：
1. 创建一个监听ACTION_BATTERY_CHANGED事件的intentFilter。
2. 创建一个BroadcastReceiver对象，该对象可以接收broadcast intent。
3. 注册BroadcastReceiver对象来监听ACTION_BATTERY_CHANGED事件。
4. 在BroadcastReceiver对象中，重写onReceive方法，在onReceive方法的传入参数intent里获取需要的电池状态信息。
5. 在生命周期结束时，取消step4中的注册。

[java]view
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public class BatteryMonitorActivity extends Activity {

private TextView batterLevel;  
private BroadcastReceiver batteryLevelRcvr;  
private IntentFilter batteryLevelFilter;  

@Override  
public void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState);  
    setContentView(R.layout.main);  
    batterLevel = (TextView) findViewById(R.id.batteryLevel);  
    monitorBatteryState();  
}  

@Override  
protected void onDestroy() {  
    super.onDestroy();  
    unregisterReceiver(batteryLevelRcvr);  
}  

private void monitorBatteryState() {  
    batteryLevelRcvr = new BroadcastReceiver() {  

        public void onReceive(Context context, Intent intent) {  
            StringBuilder sb = new StringBuilder();  
            int rawlevel = intent.getIntExtra("level", -1);  
            int scale = intent.getIntExtra("scale", -1);  
            int status = intent.getIntExtra("status", -1);  
            int health = intent.getIntExtra("health", -1);  
            int level = -1; // percentage, or -1 for unknown  
            if (rawlevel >= 0 && scale > 0) {  
                level = (rawlevel * 100) / scale;  
            }  
            sb.append("The phone");  
            if (BatteryManager.BATTERY_HEALTH_OVERHEAT == health) {  
                sb.append("'s battery feels very hot!");  
            } else {  
                switch (status) {  
                case BatteryManager.BATTERY_STATUS_UNKNOWN:  
                    sb.append("no battery.");  
                    break;  
                case BatteryManager.BATTERY_STATUS_CHARGING:  
                    sb.append("'s battery");  
                    if (level <= 33)  
                        sb.append(" is charging, battery level is low"  
                                + "[" + level + "]");  
                    else if (level <= 84)  
                        sb.append(" is charging." + "[" + level + "]");  
                    else  
                        sb.append(" will be fully charged.");  
                    break;  
                case BatteryManager.BATTERY_STATUS_DISCHARGING:  
                case BatteryManager.BATTERY_STATUS_NOT_CHARGING:  
                    if (level == 0)  
                        sb.append(" needs charging right away.");  
                    else if (level > 0 && level <= 33)  
                        sb.append(" is about ready to be recharged, battery level is low"  
                                + "[" + level + "]");  
                    else  
                        sb.append("'s battery level is" + "[" + level + "]");  
                    break;  
                case BatteryManager.BATTERY_STATUS_FULL:  
                    sb.append(" is fully charged.");  
                    break;  
                default:  
                    sb.append("'s battery is indescribable!");  
                    break;  
                }  
            }  
            sb.append(' ');  
            batterLevel.setText(sb.toString());  
        }  
    };  
    batteryLevelFilter = new IntentFilter(Intent.ACTION_BATTERY_CHANGED);  
    registerReceiver(batteryLevelRcvr, batteryLevelFilter);  
}  

}

[html]view
plaincopyprint?

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android&quot;
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<TextView
android:id="@+id/batteryLevel"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_vertical|center_horizontal"
android:textSize="50dip">
</TextView>
</LinearLayout>

Android的上层实现显示手机电池电量是通过监听实现，当电池电量改变时会通知到程序。
当然这个有朋友就要问了我不是想监听电池电量，我是想直接获取当前的电池电量。
其实这是同一个问题，当你在初始化监听器的时候他会自动首先获取电池的电量信息，然后后续当电池改变时同时也会通知当前电池电量的改变情况。

转自

http://www.blogjava.net/zhangqian1216/archive/2012/01/04/367858.html

http://blog.macrowen.com/Technology/3074.html

记得加权限