【转】BroadcastReceiver应用详解
2012-03-22 10:04
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問渠那得清如許?為有源頭活水來。南宋.朱熹《觀書有感》
据说程序员是最爱学习的群体,IT男都知道,这个行业日新月异,必须不断地学习新知识,不断地为自己注入新鲜的血液,才能使自己跟上技术的步伐。
今天我们来讲一下Android中BroadcastReceiver的相关知识。
BroadcastReceiver也就是“广播接收者”的意思,顾名思义,它就是用来接收来自系统和应用中的广播。
在Android系统中,广播体现在方方面面,例如当开机完成后系统会产生一条广播,接收到这条广播就能实现开机启动服务的功能;当网络状态改变时系统会产生一条广播,接收到这条广播就能及时地做出提示和保存数据等操作;当电池电量改变时,系统会产生一条广播,接收到这条广播就能在电量低时告知用户及时保存进度,等等。
Android中的广播机制设计的非常出色,很多事情原本需要开发者亲自操作的,现在只需等待广播告知自己就可以了,大大减少了开发的工作量和开发周期。而作为应用开发者,就需要数练掌握Android系统提供的一个开发利器,那就是BroadcastReceiver。下面我们就对BroadcastReceiver逐一地分析和演练,了解和掌握它的各种功能和用法。
首先,我们来演示一下创建一个BroadcastReceiver,并让这个BroadcastReceiver能够根据我们的需要来运行。
要创建自己的BroadcastReceiver对象,我们需要继承android.content.BroadcastReceiver,并实现其onReceive方法。下面我们就创建一个名为MyReceiver广播接收者:
[java]
view plaincopyprint?
package com.scott.receiver;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class MyReceiver extends BroadcastReceiver {
private static final String TAG = "MyReceiver";
@Override
public void onReceive(Context context, Intent intent) {
String msg = intent.getStringExtra("msg");
Log.i(TAG, msg);
}
}
动态注册
动态注册需要在代码中动态的指定广播地址并注册,通常我们是在Activity或Service注册一个广播,下面我们就来看一下注册的代码:
[java]
view plaincopyprint?
MyReceiver receiver = new MyReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction("android.intent.action.MY_BROADCAST");
registerReceiver(receiver, filter);
执行这样行代码就可以解决问题了。注意,这种注册方式与静态注册相反,不是常驻型的,也就是说广播会跟随程序的生命周期。
我们可以根据以上任意一种方法完成注册,当注册完成之后,这个接收者就可以正常工作了。我们可以用以下方式向其发送一条广播:
[java]
view plaincopyprint?
public void send(View view) {
Intent intent = new Intent("android.intent.action.MY_BROADCAST");
intent.putExtra("msg", "hello receiver.");
sendBroadcast(intent);
}
[java]
view plaincopyprint?
public class SecondReceiver extends BroadcastReceiver {
private static final String TAG = "NormalBroadcast";
@Override
public void onReceive(Context context, Intent intent) {
String msg = intent.getStringExtra("msg");
Log.i(TAG, "SecondReceiver: " + msg);
}
}
看来这三个接收者都接收到这条广播了,我们稍微修改一下三个接收者,在onReceive方法的最后一行添加以下代码,试图终止广播:
[java]
view plaincopyprint?
abortBroadcast();
[java]
view plaincopyprint?
public class SecondReceiver extends BroadcastReceiver {
private static final String TAG = "OrderedBroadcast";
@Override
public void onReceive(Context context, Intent intent) {
String msg = getResultExtras(true).getString("msg");
Log.i(TAG, "SecondReceiver: " + msg);
Bundle bundle = new Bundle();
bundle.putString("msg", msg + "@SecondReceiver");
setResultExtras(bundle);
}
}
代码改完之后,我们需要为三个接收者注册广播地址,我们修改一下AndroidMainfest.xml文件:
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<receiver android:name=".FirstReceiver">
<intent-filter android:priority="1000">
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
<receiver android:name=".SecondReceiver">
<intent-filter android:priority="999">
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
<receiver android:name=".ThirdReceiver">
<intent-filter android:priority="998">
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
所以我们在AndroidMainfest.xml中定义一个权限:
[html]
view plaincopyprint?
<permission android:protectionLevel="normal"
android:name="scott.permission.MY_BROADCAST_PERMISSION" />
然后我们点击发送按钮发送一条广播,控制台打印如下:
我们看到接收是按照顺序的,第一个和第二个都在结果集中加入了自己的标记,并且向优先级低的接收者传递下去。
既然是顺序传递,试着终止这种传递,看一看效果如何,我们修改FirstReceiver的代码,在onReceive的最后一行添加以下代码:
[java]
view plaincopyprint?
abortBroadcast();
[java]
view plaincopyprint?
package com.scott.receiver;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
public class MsgPushService extends Service {
private static final String TAG = "MsgPushService";
@Override
public void onCreate() {
super.onCreate();
Log.i(TAG, "onCreate called.");
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i(TAG, "onStartCommand called.");
return super.onStartCommand(intent, flags, startId);
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
[html]
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<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
[html]
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<receiver android:name=".NetworkStateReceiver">
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
3.电量变化
如果我们阅读软件,可能是全屏阅读,这个时候用户就看不到剩余的电量,我们就可以为他们提供电量的信息。要想做到这一点,我们需要接收一条电量变化的广播,然后获取百分比信息,这听上去挺简单的,我们就来实现以下:
[java]
view plaincopyprint?
package com.scott.receiver;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.BatteryManager;
import android.util.Log;
public class BatteryChangedReceiver extends BroadcastReceiver {
private static final String TAG = "BatteryChangedReceiver";
@Override
public void onReceive(Context context, Intent intent) {
int currLevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0); //当前电量
int total = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 1); //总电量
int percent = currLevel * 100 / total;
Log.i(TAG, "battery: " + percent + "%");
}
}
[java]
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Intent batteryIntent = getApplicationContext().registerReceiver(null,
new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
int currLevel = batteryIntent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
int total = batteryIntent.getIntExtra(BatteryManager.EXTRA_SCALE, 1);
int percent = currLevel * 100 / total;
Log.i("battery", "battery: " + percent + "%");
据说程序员是最爱学习的群体,IT男都知道,这个行业日新月异,必须不断地学习新知识,不断地为自己注入新鲜的血液,才能使自己跟上技术的步伐。
今天我们来讲一下Android中BroadcastReceiver的相关知识。
BroadcastReceiver也就是“广播接收者”的意思,顾名思义,它就是用来接收来自系统和应用中的广播。
在Android系统中,广播体现在方方面面,例如当开机完成后系统会产生一条广播,接收到这条广播就能实现开机启动服务的功能;当网络状态改变时系统会产生一条广播,接收到这条广播就能及时地做出提示和保存数据等操作;当电池电量改变时,系统会产生一条广播,接收到这条广播就能在电量低时告知用户及时保存进度,等等。
Android中的广播机制设计的非常出色,很多事情原本需要开发者亲自操作的,现在只需等待广播告知自己就可以了,大大减少了开发的工作量和开发周期。而作为应用开发者,就需要数练掌握Android系统提供的一个开发利器,那就是BroadcastReceiver。下面我们就对BroadcastReceiver逐一地分析和演练,了解和掌握它的各种功能和用法。
首先,我们来演示一下创建一个BroadcastReceiver,并让这个BroadcastReceiver能够根据我们的需要来运行。
要创建自己的BroadcastReceiver对象,我们需要继承android.content.BroadcastReceiver,并实现其onReceive方法。下面我们就创建一个名为MyReceiver广播接收者:
[java]
view plaincopyprint?
package com.scott.receiver;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.util.Log;
public class MyReceiver extends BroadcastReceiver {
private static final String TAG = "MyReceiver";
@Override
public void onReceive(Context context, Intent intent) {
String msg = intent.getStringExtra("msg");
Log.i(TAG, msg);
}
}
[html] view plaincopyprint? <receiver android:name=".MyReceiver"> <intent-filter> <action android:name="android.intent.action.MY_BROADCAST"/> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </receiver> <receiver android:name=".MyReceiver"> <intent-filter> <action android:name="android.intent.action.MY_BROADCAST"/> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> & 4000 lt;/receiver>配置了以上信息之后,只要是android.intent.action.MY_BROADCAST这个地址的广播,MyReceiver都能够接收的到。注意,这种方式的注册是常驻型的,也就是说当应用关闭后,如果有广播信息传来,MyReceiver也会被系统调用而自动运行。
动态注册
动态注册需要在代码中动态的指定广播地址并注册,通常我们是在Activity或Service注册一个广播,下面我们就来看一下注册的代码:
[java]
view plaincopyprint?
MyReceiver receiver = new MyReceiver();
IntentFilter filter = new IntentFilter();
filter.addAction("android.intent.action.MY_BROADCAST");
registerReceiver(receiver, filter);
[java] view plaincopyprint? @Override protected void onDestroy() { super.onDestroy(); unregisterReceiver(receiver); } @Override protected void onDestroy() { super.onDestroy(); unregisterReceiver(receiver); }
执行这样行代码就可以解决问题了。注意,这种注册方式与静态注册相反,不是常驻型的,也就是说广播会跟随程序的生命周期。
我们可以根据以上任意一种方法完成注册,当注册完成之后,这个接收者就可以正常工作了。我们可以用以下方式向其发送一条广播:
[java]
view plaincopyprint?
public void send(View view) {
Intent intent = new Intent("android.intent.action.MY_BROADCAST");
intent.putExtra("msg", "hello receiver.");
sendBroadcast(intent);
}
[java] view plaincopyprint? package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class FirstReceiver extends BroadcastReceiver { private static final String TAG = "NormalBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = intent.getStringExtra("msg"); Log.i(TAG, "FirstReceiver: " + msg); } } package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class FirstReceiver extends BroadcastReceiver { private static final String TAG = "NormalBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = intent.getStringExtra("msg"); Log.i(TAG, "FirstReceiver: " + msg); } }
[java]
view plaincopyprint?
public class SecondReceiver extends BroadcastReceiver {
private static final String TAG = "NormalBroadcast";
@Override
public void onReceive(Context context, Intent intent) {
String msg = intent.getStringExtra("msg");
Log.i(TAG, "SecondReceiver: " + msg);
}
}
[java] view plaincopyprint? public class ThirdReceiver extends BroadcastReceiver { private static final String TAG = "NormalBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = intent.getStringExtra("msg"); Log.i(TAG, "ThirdReceiver: " + msg); } } public class ThirdReceiver extends BroadcastReceiver { private static final String TAG = "NormalBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = intent.getStringExtra("msg"); Log.i(TAG, "ThirdReceiver: " + msg); } }然后再次点击发送按钮,发送一条广播,控制台打印如下:
看来这三个接收者都接收到这条广播了,我们稍微修改一下三个接收者,在onReceive方法的最后一行添加以下代码,试图终止广播:
[java]
view plaincopyprint?
abortBroadcast();
[java] view plaincopyprint? package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.util.Log; public class FirstReceiver extends BroadcastReceiver { private static final String TAG = "OrderedBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = intent.getStringExtra("msg"); Log.i(TAG, "FirstReceiver: " + msg); Bundle bundle = new Bundle(); bundle.putString("msg", msg + "@FirstReceiver"); setResultExtras(bundle); } } package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.os.Bundle; import android.util.Log; public class FirstReceiver extends BroadcastReceiver { private static final String TAG = "OrderedBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = intent.getStringExtra("msg"); Log.i(TAG, "FirstReceiver: " + msg); Bundle bundle = new Bundle(); bundle.putString("msg", msg + "@FirstReceiver"); setResultExtras(bundle); } }
[java]
view plaincopyprint?
public class SecondReceiver extends BroadcastReceiver {
private static final String TAG = "OrderedBroadcast";
@Override
public void onReceive(Context context, Intent intent) {
String msg = getResultExtras(true).getString("msg");
Log.i(TAG, "SecondReceiver: " + msg);
Bundle bundle = new Bundle();
bundle.putString("msg", msg + "@SecondReceiver");
setResultExtras(bundle);
}
}
[java] view plaincopyprint? public class ThirdReceiver extends BroadcastReceiver { private static final String TAG = "OrderedBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = getResultExtras(true).getString("msg"); Log.i(TAG, "ThirdReceiver: " + msg); } } public class ThirdReceiver extends BroadcastReceiver { private static final String TAG = "OrderedBroadcast"; @Override public void onReceive(Context context, Intent intent) { String msg = getResultExtras(true).getString("msg"); Log.i(TAG, "ThirdReceiver: " + msg); } }我们注意到,在FirstReceiver和SecondReceiver中最后都使用了setResultExtras方法将一个Bundle对象设置为结果集对象,传递到下一个接收者那里,这样以来,优先级低的接收者可以用getResultExtras获取到最新的经过处理的信息集合。
代码改完之后,我们需要为三个接收者注册广播地址,我们修改一下AndroidMainfest.xml文件:
[html]
view plaincopyprint?
<receiver android:name=".FirstReceiver">
<intent-filter android:priority="1000">
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
<receiver android:name=".SecondReceiver">
<intent-filter android:priority="999">
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
<receiver android:name=".ThirdReceiver">
<intent-filter android:priority="998">
<action android:name="android.intent.action.MY_BROADCAST"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
[java] view plaincopyprint? public void send(View view) { Intent intent = new Intent("android.intent.action.MY_BROADCAST"); intent.putExtra("msg", "hello receiver."); sendOrderedBroadcast(intent, "scott.permission.MY_BROADCAST_PERMISSION"); } public void send(View view) { Intent intent = new Intent("android.intent.action.MY_BROADCAST"); intent.putExtra("msg", "hello receiver."); sendOrderedBroadcast(intent, "scott.permission.MY_BROADCAST_PERMISSION"); }注意,使用sendOrderedBroadcast方法发送有序广播时,需要一个权限参数,如果为null则表示不要求接收者声明指定的权限,如果不为null,则表示接收者若要接收此广播,需声明指定权限。这样做是从安全角度考虑的,例如系统的短信就是有序广播的形式,一个应用可能是具有拦截垃圾短信的功能,当短信到来时它可以先接受到短信广播,必要时终止广播传递,这样的软件就必须声明接收短信的权限。
所以我们在AndroidMainfest.xml中定义一个权限:
[html]
view plaincopyprint?
<permission android:protectionLevel="normal"
android:name="scott.permission.MY_BROADCAST_PERMISSION" />
[html] view plaincopyprint? <uses-permission android:name="scott.permission.MY_BROADCAST_PERMISSION" /> <uses-permission android:name="scott.permission.MY_BROADCAST_PERMISSION" />关于这部分如果有不明白的地方可以参考我之前写过的一篇文章:Android声明和使用权限
然后我们点击发送按钮发送一条广播,控制台打印如下:
我们看到接收是按照顺序的,第一个和第二个都在结果集中加入了自己的标记,并且向优先级低的接收者传递下去。
既然是顺序传递,试着终止这种传递,看一看效果如何,我们修改FirstReceiver的代码,在onReceive的最后一行添加以下代码:
[java]
view plaincopyprint?
abortBroadcast();
[java] view plaincopyprint? package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class BootCompleteReceiver extends BroadcastReceiver { private static final String TAG = "BootCompleteReceiver"; @Override public void onReceive(Context context, Intent intent) { Intent service = new Intent(context, MsgPushService.class); context.startService(service); Log.i(TAG, "Boot Complete. Starting MsgPushService..."); } } package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.util.Log; public class BootCompleteReceiver extends BroadcastReceiver { private static final String TAG = "BootCompleteReceiver"; @Override public void onReceive(Context context, Intent intent) { Intent service = new Intent(context, MsgPushService.class); context.startService(service); Log.i(TAG, "Boot Complete. Starting MsgPushService..."); } }
[java]
view plaincopyprint?
package com.scott.receiver;
import android.app.Service;
import android.content.Intent;
import android.os.IBinder;
import android.util.Log;
public class MsgPushService extends Service {
private static final String TAG = "MsgPushService";
@Override
public void onCreate() {
super.onCreate();
Log.i(TAG, "onCreate called.");
}
@Override
public int onStartCommand(Intent intent, int flags, int startId) {
Log.i(TAG, "onStartCommand called.");
return super.onStartCommand(intent, flags, startId);
}
@Override
public IBinder onBind(Intent arg0) {
return null;
}
}
[html] view plaincopyprint? <!-- 开机广播接受者 --> <receiver android:name=".BootCompleteReceiver"> <intent-filter> <!-- 注册开机广播地址--> <action android:name="android.intent.action.BOOT_COMPLETED"/> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </receiver> <!-- 消息推送服务 --> <service android:name=".MsgPushService"/> <!-- 开机广播接受者 --> <receiver android:name=".BootCompleteReceiver"> <intent-filter> <!-- 注册开机广播地址--> <action android:name="android.intent.action.BOOT_COMPLETED"/> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </receiver> <!-- 消息推送服务 --> <service android:name=".MsgPushService"/>我们看到BootCompleteReceiver注册了“android.intent.action.BOOT_COMPLETED”这个开机广播地址,从安全角度考虑,系统要求必须声明接收开机启动广播的权限,于是我们再声明使用下面的权限:
[html]
view plaincopyprint?
<uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED" />
[java] view plaincopyprint? package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.net.ConnectivityManager; import android.net.NetworkInfo; import android.util.Log; import android.widget.Toast; public class NetworkStateReceiver extends BroadcastReceiver { private static final String TAG = "NetworkStateReceiver"; @Override public void onReceive(Context context, Intent intent) { Log.i(TAG, "network state changed."); if (!isNetworkAvailable(context)) { Toast.makeText(context, "network disconnected!", 0).show(); } } /** * 网络是否可用 * * @param context * @return */ public static boolean isNetworkAvailable(Context context) { ConnectivityManager mgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo[] info = mgr.getAllNetworkInfo(); if (info != null) { for (int i = 0; i < info.length; i++) { if (info[i].getState() == NetworkInfo.State.CONNECTED) { return true; } } } return false; } } package com.scott.receiver; import android.content.BroadcastReceiver; import android.content.Context; import android.content.Intent; import android.net.ConnectivityManager; import android.net.NetworkInfo; import android.util.Log; import android.widget.Toast; public class NetworkStateReceiver extends BroadcastReceiver { private static final String TAG = "NetworkStateReceiver"; @Override public void onReceive(Context context, Intent intent) { Log.i(TAG, "network state changed."); if (!isNetworkAvailable(context)) { Toast.makeText(context, "network disconnected!", 0).show(); } } /** * 网络是否可用 * * @param context * @return */ public static boolean isNetworkAvailable(Context context) { ConnectivityManager mgr = (ConnectivityManager) context.getSystemService(Context.CONNECTIVITY_SERVICE); NetworkInfo[] info = mgr.getAllNetworkInfo(); if (info != null) { for (int i = 0; i < info.length; i++) { if (info[i].getState() == NetworkInfo.State.CONNECTED) { return true; } } } return false; } }再注册一下这个接收者的信息:
[html]
view plaincopyprint?
<receiver android:name=".NetworkStateReceiver">
<intent-filter>
<action android:name="android.net.conn.CONNECTIVITY_CHANGE"/>
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</receiver>
[html] view plaincopyprint? <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/> <uses-permission android:name="android.permission.ACCESS_NETWORK_STATE"/>我们可以测试一下,比如关闭WiFi,看看有什么效果。
3.电量变化
如果我们阅读软件,可能是全屏阅读,这个时候用户就看不到剩余的电量,我们就可以为他们提供电量的信息。要想做到这一点,我们需要接收一条电量变化的广播,然后获取百分比信息,这听上去挺简单的,我们就来实现以下:
[java]
view plaincopyprint?
package com.scott.receiver;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.BatteryManager;
import android.util.Log;
public class BatteryChangedReceiver extends BroadcastReceiver {
private static final String TAG = "BatteryChangedReceiver";
@Override
public void onReceive(Context context, Intent intent) {
int currLevel = intent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0); //当前电量
int total = intent.getIntExtra(BatteryManager.EXTRA_SCALE, 1); //总电量
int percent = currLevel * 100 / total;
Log.i(TAG, "battery: " + percent + "%");
}
}
[html] view plaincopyprint? <receiver android:name=".BatteryChangedReceiver"> <intent-filter> <action android:name="android.intent.action.BATTERY_CHANGED"/> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </receiver> <receiver android:name=".BatteryChangedReceiver"> <intent-filter> <action android:name="android.intent.action.BATTERY_CHANGED"/> <category android:name="android.intent.category.DEFAULT" /> </intent-filter> </receiver>当然,有些时候我们是要立即获取电量的,而不是等电量变化的广播,比如当阅读软件打开时立即显示出电池电量。我们可以按以下方式获取:
[java]
view plaincopyprint?
Intent batteryIntent = getApplicationContext().registerReceiver(null,
new IntentFilter(Intent.ACTION_BATTERY_CHANGED));
int currLevel = batteryIntent.getIntExtra(BatteryManager.EXTRA_LEVEL, 0);
int total = batteryIntent.getIntExtra(BatteryManager.EXTRA_SCALE, 1);
int percent = currLevel * 100 / total;
Log.i("battery", "battery: " + percent + "%");
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