MSM8909+Android5.1.1之BSP开发---电池管理2---BatteryInfo.java

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MSM8909+Android5.1.1之BSP开发---电池管理2---BatteryInfo.java

先来借用MTK对电池管理的框架图

图1

通过电话测试指令：*#*#4636#*#*可以弹出Testing界面

图2

选择Battery information，进入：

图3

我们接入USB或是DC充电的时候，Power plug都显示的时Unknown

说明底层就判断为Unknown类型，此问题要查清楚

BatteryInfo对应的代码为packages\apps\Settings\src\com\android\settings\BatteryInfo.java

1.     \packages\apps\Settings\AndroidManifest.xml

<activityandroid:name="BatteryInfo" android:label="@string/battery_info_label"
                 android:taskAffinity="com.android.settings"
                 android:parentActivityName="Settings">
           <intent-filter>
                <actionandroid:name="android.intent.action.MAIN" />
                <categoryandroid:name="android.intent.category.DEVELOPMENT_PREFERENCE" />
                <categoryandroid:name="android.intent.category.VOICE_LAUNCH" />
           </intent-filter>
       </activity>

(1)  android:label

android:label="@string/battery_info_label"，label表示标签，@表示引用，表示从string这个文件中引用battery_info_label这个键值的值，

\packages\apps\Settings\res\values\ strings.xml中对应的值如下：

<!-- The title of the activity to seebattery info. -->

<stringname="battery_info_label">Battery info</string>

(2)  android:taskAffinity

android:taskAffinity="com.android.settings"表示BatteryInfo Activity希望进入com.android.settings这个task。

Activity的归属，也就是Activity应该在哪个Task中，Activity与Task的吸附关系。我们知道，一般情况下在同一个应用中，启动的Activity都在同一个Task中，它们在该Task中度过自己的生命周期，这些Activity是从一而终的好榜样。

    那么为什么我们创建的Activity会进入这个Task中？它们会转到其它的Task中吗？如果转到其它的Task中，它们会到什么样的Task中去？

    解决这些问题的关键，在于每个Activity的taskAffinity属性。

    每个Activity都有taskAffinity属性，这个属性指出了它希望进入的Task。如果一个Activity没有显式的指明该Activity的taskAffinity，那么它的这个属性就等于Application指明的taskAffinity，如果Application也没有指明，那么该taskAffinity的值就等于包名。而Task也有自己的affinity属性，它的值等于它的根Activity的taskAffinity的值。

2.     BatteryInfo.java代码分析

2.1  onCreate()

@Override
   public void onCreate(Bundle icicle) {
       super.onCreate(icicle);
 
       setContentView(R.layout.battery_info);
 
       // create the IntentFilter that will be used to listen
       // to battery status broadcasts
       mIntentFilter = new IntentFilter();
       mIntentFilter.addAction(Intent.ACTION_BATTERY_CHANGED);
    }

(1)   R.layout.battery_info

其值在packages\apps\Settings\res\layout\battery_info.xml定义

(2)   创建一个IntentFilter类的对象mIntentFilter

用于监听电池状态广播。

(3)   mIntentFilter.addAction(Intent.ACTION_BATTERY_CHANGED);

为此IntentFilter增加一个ACTION_BATTERY_CHANGED的action，也就是说当其他Activity、或是Service等发送包含有ACTION_BATTERY_CHANGED的intent时，BatteryInfo就执行更新电池状态的动作

2.2  onResume()

public void onResume() {
       super.onResume();
 
       mStatus = (TextView)findViewById(R.id.status);
       mPower = (TextView)findViewById(R.id.power);
       mLevel = (TextView)findViewById(R.id.level);
       mScale = (TextView)findViewById(R.id.scale);
       mHealth = (TextView)findViewById(R.id.health);
       mTechnology = (TextView)findViewById(R.id.technology);
       mVoltage = (TextView)findViewById(R.id.voltage);
       mTemperature = (TextView)findViewById(R.id.temperature);
       mUptime = (TextView) findViewById(R.id.uptime);
       
       // Get awake time plugged in and on battery
       mBatteryStats =IBatteryStats.Stub.asInterface(ServiceManager.getService(
                BatteryStats.SERVICE_NAME));
       mScreenStats = IPowerManager.Stub.asInterface(ServiceManager.getService(POWER_SERVICE));
       mHandler.sendEmptyMessageDelayed(EVENT_TICK, 3000);
       
       registerReceiver(mIntentReceiver, mIntentFilter);
    }

在onResume()方法中通过registerReceiver(mIntentReceiver,mIntentFilter);注册一个Receiver，最终在onReceive()方法中收到值为ACTION_BATTERY_CHANGED的action时，BatteryInfo这个Activity要更新电池状态信息。

(1)  创建一个Handler

mHandler.sendEmptyMessageDelayed(EVENT_TICK,3000);使用到Handler，其创建如下：

private Handler mHandler = new Handler() {
        @Override
       public void handleMessage(Message msg) {
           switch (msg.what) {
                case EVENT_TICK:
                    updateBatteryStats();
                   sendEmptyMessageDelayed(EVENT_TICK, 1000);
                   
                    break;
           }
       }
};

重写handleMessage()用于处理消息EVENT_TICK，在收到此消息后，调用updateBatteryStats()更新电池状态，并1000ms后发送EVENT_TICK消息。

(2)  注册一个监听器 

/**
   *Listens for intent broadcasts
   */
   private IntentFilter  mIntentFilter;
 
   private BroadcastReceiver mIntentReceiver = new BroadcastReceiver() {
       @Override
       public void onReceive(Context context, Intent intent) {
           String action = intent.getAction();
           if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
                int plugType =intent.getIntExtra("plugged", 0);
 
                mLevel.setText("" +intent.getIntExtra("level", 0));
                mScale.setText("" +intent.getIntExtra("scale", 0));
                mVoltage.setText("" +intent.getIntExtra("voltage", 0) + " "
                        +getString(R.string.battery_info_voltage_units));
               mTemperature.setText("" +tenthsToFixedString(intent.getIntExtra("temperature", 0))
                        +getString(R.string.battery_info_temperature_units));
               mTechnology.setText("" +intent.getStringExtra("technology"));
               
               mStatus.setText(Utils.getBatteryStatus(getResources(), intent));
 
             
                switch (plugType) {
                    case 0:                       mPower.setText(getString(R.string.battery_info_power_unplugged));
                        break;
                    case BatteryManager.BATTERY_PLUGGED_AC:                       mPower.setText(getString(R.string.battery_info_power_ac));
                        break;
                    case BatteryManager.BATTERY_PLUGGED_USB:                       mPower.setText(getString(R.string.battery_info_power_usb));
                        break;
                    caseBatteryManager.BATTERY_PLUGGED_WIRELESS:
                       mPower.setText(getString(R.string.battery_info_power_wireless));
                        break;
                    case(BatteryManager.BATTERY_PLUGGED_AC|BatteryManager.BATTERY_PLUGGED_USB):                       mPower.setText(getString(R.string.battery_info_power_ac_usb));
                        break;
                    default:                        mPower.setText(getString(R.string.battery_info_power_unknown));
                        break;
                }
               
                int health =intent.getIntExtra("health", BatteryManager.BATTERY_HEALTH_UNKNOWN);
                String healthString;
                if (health ==BatteryManager.BATTERY_HEALTH_GOOD) {
                    healthString =getString(R.string.battery_info_health_good);
                } else if (health ==BatteryManager.BATTERY_HEALTH_OVERHEAT) {
                   healthString =getString(R.string.battery_info_health_overheat);
                } else if (health ==BatteryManager.BATTERY_HEALTH_DEAD) {
                    healthString =getString(R.string.battery_info_health_dead);
                } else if (health ==BatteryManager.BATTERY_HEALTH_OVER_VOLTAGE) {
                    healthString =getString(R.string.battery_info_health_over_voltage);
                } else if (health ==BatteryManager.BATTERY_HEALTH_UNSPECIFIED_FAILURE) {
                    healthString =getString(R.string.battery_info_health_unspecified_failure);
                } else if (health ==BatteryManager.BATTERY_HEALTH_COLD) {
                    healthString =getString(R.string.battery_info_health_cold);
                } else {
                    healthString =getString(R.string.battery_info_health_unknown);
                }
                mHealth.setText(healthString);
           }
       }
   };

1)     Battery status信息的更新

其中Battery status有些特别：

mStatus.setText(Utils.getBatteryStatus(getResources(),intent));

看packages\apps\Settings\src\com\android\settings\Utils.java\getBatteryStatus()的实现：

public static StringgetBatteryStatus(Resources res, Intent batteryChangedIntent) {
       final Intent intent = batteryChangedIntent;
 
       int plugType = intent.getIntExtra(BatteryManager.EXTRA_PLUGGED, 0);
       int status = intent.getIntExtra(BatteryManager.EXTRA_STATUS,
               BatteryManager.BATTERY_STATUS_UNKNOWN);
       String statusString;
       if (status == BatteryManager.BATTERY_STATUS_CHARGING) {
           int resId;
           if (plugType == BatteryManager.BATTERY_PLUGGED_AC) {
                resId =R.string.battery_info_status_charging_ac;
           } else if (plugType == BatteryManager.BATTERY_PLUGGED_USB) {
                resId =R.string.battery_info_status_charging_usb;
           } else if (plugType == BatteryManager.BATTERY_PLUGGED_WIRELESS) {
                resId =R.string.battery_info_status_charging_wireless;
           } else {
                resId =R.string.battery_info_status_charging;
           }
           statusString = res.getString(resId);
        } else if (status ==BatteryManager.BATTERY_STATUS_DISCHARGING) {
           statusString = res.getString(R.string.battery_info_status_discharging);
       } else if (status == BatteryManager.BATTERY_STATUS_NOT_CHARGING) {
           statusString = res.getString(R.string.battery_info_status_not_charging);
       } else if (status == BatteryManager.BATTERY_STATUS_FULL) {
           statusString = res.getString(R.string.battery_info_status_full);
       } else {
           statusString = res.getString(R.string.battery_info_status_unknown);
       }
 
       return statusString;
}

从上面可知，plugType是unknown，所以从\packages\apps\Settings\res\values\strings.xml的battery_info_status_charging获取到充电状态是Charing，如下：

<stringname="battery_info_status_charging">Charging</string>

2)     如何获取电池的信息

public void onReceive(Context context,Intent intent) {
           String action = intent.getAction();
           if (action.equals(Intent.ACTION_BATTERY_CHANGED)) {
                int plugType =intent.getIntExtra("plugged", 0);

这是上面其中一段代码，收到广播，且其中intent的action的值为 ACTION_BATTERY_CHANGED时就从intent中读取plugged的值，这个intent是由BatteryService广播出来的。

2.3  onPause()

@Override
   public void onPause() {
       super.onPause();
       mHandler.removeMessages(EVENT_TICK);
       Slog.e(TAG, "BatteryInfo--->onPause()");
       // we are no longer on the screen stop the observers
       unregisterReceiver(mIntentReceiver);
}

比较简单，就是删除EVENT_TICK消息和注销监听器mIntentReceiver

MSM8909+Android5.1.1之BSP开发---电池管理2---BatteryInfo.java

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原文地址：http://blog.csdn.net/loongembedded/article/details/50364648