MSM8909+Android5.1.1之BSP開發---電池管理2---BatteryInfo.java

MSM8909+Android5.1.1之BSP開發---電池管理2---BatteryInfo.java

 

先來借用MTK對電池管理的框架圖

 

圖1

 

通過電話測試指令：*#*#4636#*#*可以彈出Testing界面

 

圖2

選擇Battery information，進入：

 

圖3

我們接入USB或是DC充電的時候，Power plug都顯示的時Unknown

說明底層就判斷為Unknown類型，此問題要查清楚

 

BatteryInfo對應的代碼為packages\apps\Settings\src\com\android\settings\BatteryInfo.java

 

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

 

 

(1) android:label

android:label="@string/battery_info_label"，label表示標簽，@表示引用，表示從string這個文件中引用battery_info_label這個鍵值的值，

\packages\apps\Settings\res\values\ strings.xml中對應的值如下：

Battery info

 

(2) android:taskAffinity

android:taskAffinity="com.android.settings"表示BatteryInfo Activity希望進入com.android.settings這個task。

 

Activity的歸屬，也就是Activity應該在哪個Task中，Activity與Task的吸附關系。我們知道，一般情況下在同一個應用中，啟動的Activity都在同一個Task中，它們在該Task中度過自己的生命周期，這些Activity是從一而終的好榜樣。

 

那麼為什麼我們創建的Activity會進入這個Task中？它們會轉到其它的Task中嗎？如果轉到其它的Task中，它們會到什麼樣的Task中去？

 

解決這些問題的關鍵，在於每個Activity的taskAffinity屬性。

 

每個Activity都有taskAffinity屬性，這個屬性指出了它希望進入的Task。如果一個Activity沒有顯式的指明該Activity的taskAffinity，那麼它的這個屬性就等於Application指明的taskAffinity，如果Application也沒有指明，那麼該taskAffinity的值就等於包名。而Task也有自己的affinity屬性，它的值等於它的根Activity的taskAffinity的值。

 

2. BatteryInfo.java代碼分析

 

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定義

(2) 創建一個IntentFilter類的對象mIntentFilter

用於監聽電池狀態廣播。

 

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

為此IntentFilter增加一個ACTION_BATTERY_CHANGED的action，也就是說當其他Activity、或是Service等發送包含有ACTION_BATTERY_CHANGED的intent時，BatteryInfo就執行更新電池狀態的動作

 

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()方法中通過registerReceiver(mIntentReceiver,mIntentFilter);注冊一個Receiver，最終在onReceive()方法中收到值為ACTION_BATTERY_CHANGED的action時，BatteryInfo這個Activity要更新電池狀態信息。

 

(1) 創建一個Handler

mHandler.sendEmptyMessageDelayed(EVENT_TICK,3000);使用到Handler，其創建如下：

 

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

 

重寫handleMessage()用於處理消息EVENT_TICK，在收到此消息後，調用updateBatteryStats()更新電池狀態，並1000ms後發送EVENT_TICK消息。

 

(2) 注冊一個監聽器

 

/**
   *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有些特別：

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

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

 

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;
}

 

從上面可知，plugType是unknown，所以從\packages\apps\Settings\res\values\strings.xml的battery_info_status_charging獲取到充電狀態是Charing，如下：

Charging

 

2) 如何獲取電池的信息

 

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

 

這是上面其中一段代碼，收到廣播，且其中intent的action的值為 ACTION_BATTERY_CHANGED時就從intent中讀取plugged的值，這個intent是由BatteryService廣播出來的。

 

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);
}

 

比較簡單，就是刪除EVENT_TICK消息和注銷監聽器mIntentReceiver