通过查看 PhoneWindowManager 中 power 相关流程，发现Android 原生code中已经添加了对Power键连按的接口，目前可以定义按一次、按两次及按三次时对应的响应操作，今天小编就来说说关于android如何通过代码重启应用?下面更多详细答案一起来看看吧!

android如何通过代码重启应用

通过查看 PhoneWindowManager 中 power 相关流程，发现Android 原生code中已经添加了对Power键连按的接口，目前可以定义按一次、按两次及按三次时对应的响应操作。

Android中对Power键连按次数的定义如下：frameworks\base\core\res\res\values\config.xml

短按一次power键系统定义：

<!-- Control the behavior when the user short presses the power button. 0 - Nothing 1 - Go to sleep (doze) 2 - Really go to sleep (don't doze) 3 - Really go to sleep and go home (don't doze) 4 - Go to home 5 - Dismiss IME if shown. Otherwise go to home --> <integer name="config_shortPressOnPowerBehavior">1</integer>

连续短按两次power键系统定义：

<!-- Control the behavior when the user double presses the power button. 0 - Nothing 1 - Toggle theater mode setting 2 - Brightness boost --> <integer name="config_doublePressOnPowerBehavior">0</integer>

连续短按三次power键系统定义：

<!-- Control the behavior when the user triple presses the power button. 0 - Nothing 1 - Toggle theater mode setting 2 - Brightness boost --> <integer name="config_triplePressOnPowerBehavior">0</integer>

可以看到短按两次和短按三次都是定义的 0，对应为 nothing，即不做任何操作。

power键在config中的定义，最终是在PhoneWindowManager.java 的 powerPress()方法中判断和实现。frameworks\base\services\core\java\com\android\server\policy\PhoneWindowManager.java

private void powerPress(long eventTime, boolean interactive, int count) { if (mScreenOnEarly && !mScreenOnFully) { Slog.i(TAG, "Suppressed redundant power key press while " "already in the process of turning the screen on."); return; } if (count == 2) {//短按两次power键的实现 powerMultiPressAction(eventTime, interactive, mDoublePressOnPowerBehavior); } else if (count == 3) {{//短按三次power键的实现 powerMultiPressAction(eventTime, interactive, mTriplePressOnPowerBehavior); } else if (interactive && !mBeganFromNonInteractive) { switch (mShortPressOnPowerBehavior) { case SHORT_PRESS_POWER_NOTHING:break; case SHORT_PRESS_POWER_GO_TO_SLEEP:goToSleep(eventTime, PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON, 0);break; case SHORT_PRESS_POWER_REALLY_GO_TO_SLEEP:goToSleep(eventTime, PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON, PowerManager.GO_TO_SLEEP_FLAG_NO_DOZE);break; case SHORT_PRESS_POWER_REALLY_GO_TO_SLEEP_AND_GO_HOME:goToSleep(eventTime, PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON, PowerManager.GO_TO_SLEEP_FLAG_NO_DOZE);launchHomeFromHotKey();break; case SHORT_PRESS_POWER_GO_HOME:shortPressPowerGoHome();break; case SHORT_PRESS_POWER_CLOSE_IME_OR_GO_HOME: {if (mDismissImeOnBackKeyPressed) { if (mInputMethodManagerInternal == null) { mInputMethodManagerInternal = LocalServices.getService(InputMethodManagerInternal.class); } if (mInputMethodManagerInternal != null) { mInputMethodManagerInternal.hideCurrentInputMethod(); }} else { shortPressPowerGoHome();}break; } } } }

由code中发现，短按两次，三次都是在powerMultiPressAction()中实现

private void powerMultiPressAction(long eventTime, boolean interactive, int behavior) { switch (behavior) { case MULTI_PRESS_POWER_NOTHING: break; case MULTI_PRESS_POWER_THEATER_MODE: if (!isUserSetupComplete()) {Slog.i(TAG, "Ignoring toggling theater mode - device not setup.");break; } if (isTheaterModeEnabled()) {Slog.i(TAG, "Toggling theater mode off.");Settings.Global.putInt(mContext.getContentResolver(), Settings.Global.THEATER_MODE_ON, 0);if (!interactive) { wakeUpFromPowerKey(eventTime);} } else {Slog.i(TAG, "Toggling theater mode on.");Settings.Global.putInt(mContext.getContentResolver(), Settings.Global.THEATER_MODE_ON, 1);if (mGoToSleepOnButtonPressTheaterMode && interactive) { goToSleep(eventTime, PowerManager.GO_TO_SLEEP_REASON_POWER_BUTTON, 0);} } break; case MULTI_PRESS_POWER_BRIGHTNESS_BOOST: Slog.i(TAG, "Starting brightness boost."); if (!interactive) {wakeUpFromPowerKey(eventTime); } mPowerManager.boostScreenBrightness(eventTime); break; } }

正好就是config_doublePressOnPowerBehavior和config_triplePressOnPowerBehavior对应的三种状态，因此，可以以此为入口，通过自定义第四种状态，来实现自定义功能，比如：紧急呼叫功能。

附上同时所实现的连续短按三次power键实现紧急呼叫功能：

1) 自定义状态值Config.xml<integer name="config_triplePressOnPowerBehavior">3</integer>PhoneWindowManager.javastatic final int MULTI_PRESS_POWER_EMERGENCY_CALL = 3;2) 实现对应功能PhoneWindowManager.java 的 powerMultiPressAction()方法添加 case：case MULTI_PRESS_POWER_EMERGENCY_CALL:Intent callIntent = new Intent(Intent.ACTION_CALL_EMERGENCY);callIntent.setFlags(Intent.FLAG_ACTIVITY_NEW_TASK);callIntent.setData(Uri.parse("tel:112"));mContext.startActivity(callIntent);break;