狀态欄預設顯示電量百分比
在Android P 的BatteryMeterView中有內建顯示電量百分比相關代碼,是以我們隻需要将其顯示控制條件預設打開就行。
在Settings的Battery的子頁面中存在一個Battery percentage Switch選項,該選項就是用來控制電量百分比是否顯示在狀态欄的,不過預設是關閉的~
通過Battery percentage Switch選項,可以定位到android\packages\apps\Settings\res\xml\power_usage_summary.xml 檔案,有如下代碼:
<SwitchPreference
android:key="battery_percentage"
android:title="@string/battery_percentage"
android:summary="@string/battery_percentage_description" />
根據布局中的key值,可以查詢到該SwitchPreference的控制器類android\packages\apps\Settings\src\com\android\settings\display\BatteryPercentagePreferenceController.java,如下:
public class BatteryPercentagePreferenceController extends AbstractPreferenceController implements
PreferenceControllerMixin, Preference.OnPreferenceChangeListener {
private static final String KEY_BATTERY_PERCENTAGE = "battery_percentage";
public BatteryPercentagePreferenceController(Context context) {
super(context);
}
/**
*isAvailable傳回值主要控制在Settings的Battery頁面中的
*Battery percentage Switch選項是否顯示出來
*
*傳回false,Battery percentage選項将會被隐藏掉
*
*config_battery_percentage_setting_available預設值為true,
*在android\frameworks\base\core\res\res\values\config.xml中定義。
*/
@Override
public boolean isAvailable() {
return mContext.getResources()
.getBoolean(R.bool.config_battery_percentage_setting_available);
}
@Override
public String getPreferenceKey() {
return KEY_BATTERY_PERCENTAGE;
}
/**
*根據SHOW_BATTERY_PERCENT值,更改Switch顯示狀态
*在沒有取到SHOW_BATTERY_PERCENT值時候,以0為預設值
* 1:顯示,0:不顯示
*/
@Override
public void updateState(Preference preference) {
int setting = Settings.System.getInt(mContext.getContentResolver(),
SHOW_BATTERY_PERCENT, 0);
((SwitchPreference) preference).setChecked(setting == 1);
}
/**
*根據Switch狀态改變,進而更改SHOW_BATTERY_PERCENT這個系統值
*/
@Override
public boolean onPreferenceChange(Preference preference, Object newValue) {
boolean showPercentage = (Boolean) newValue;
Settings.System.putInt(mContext.getContentResolver(), SHOW_BATTERY_PERCENT,
showPercentage ? 1 : 0);
return true;
}
}
是以要想電量百分比預設顯示,隻需要找到SHOW_BATTERY_PERCENT預設值設定的地方,然後将其置為1,就預設顯示電量百分比了。
一通查找,然後并沒有發現SHOW_BATTERY_PERCENT賦初值的地方,是以需要自己手動添加一下:
在android/frameworks/base/packages/SettingsProvider/res/values/defaults.xml末尾添加一項:
<!-- Default to show battery percaent on statusbar -->
<integer name="def_show_battery_percent">1</integer>
然後該預設值寫到系統資料庫中去:
android/frameworks/base/packages/SettingsProvider/src/com/android/providers/settings/DatabaseHelper.java
private void loadSystemSettings(SQLiteDatabase db) {
SQLiteStatement stmt = null;
try {
stmt = db.compileStatement("INSERT OR IGNORE INTO system(name,value)"
+ " VALUES(?,?);");
loadBooleanSetting(stmt, Settings.System.NOTIFICATION_LIGHT_PULSE,
R.bool.def_notification_pulse);
loadUISoundEffectsSettings(stmt);
loadIntegerSetting(stmt, Settings.System.POINTER_SPEED,
R.integer.def_pointer_speed);
//為SHOW_BATTERY_PERCENT寫入預設值
loadIntegerSetting(stmt, Settings.System.SHOW_BATTERY_PERCENT, R.integer.def_show_battery_percent);
/*
* IMPORTANT: Do not add any more upgrade steps here as the global,
* secure, and system settings are no longer stored in a database
* but are kept in memory and persisted to XML.
*
* See: SettingsProvider.UpgradeController#onUpgradeLocked
*/
} finally {
if (stmt != null) stmt.close();
}
}
将SettingsProvider單編,然後push到裝置中,将裝置恢複出廠設定一下,狀态欄顯示電量百分比即可生效了!