MTK平台默认按两下power键打开相机的快捷手势，如今需求改为快捷打开手电筒，需要找到位置进行替换即可，写入节点，加入节点权限。
/frameworks/base/services/core/java/com/android/server/GestureLauncherService.java
//*/add pkg
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStreamWriter;
import java.io.Writer;
import android.util.Log;
//*/
//*/add global variable opne flashlight to switch on/off
private boolean mFlashlight = false;
//*/
if (launchCamera) {//两下power键打开相机
/*/add,repalce double open camera with open flashlight
launchCamera = handleCameraGesture(false ,
StatusBarManager.CAMERA_LAUNCH_SOURCE_POWER_DOUBLE_TAP);//1 // useWakelock
/*/
mFlashlight = !mFlashlight;
writeFlashLightFile(mFlashlight);
//*/
if (launchCamera) {
mMetricsLogger.action(MetricsEvent.ACTION_DOUBLE_TAP_POWER_CAMERA_GESTURE,
(int) powerTapInterval);
mUiEventLogger.log(GestureLauncherEvent.GESTURE_CAMERA_DOUBLE_TAP_POWER);
}
} else if (launchEmergencyGesture) {//五下power键打开紧急拨号
Slog.i(TAG, "Emergency gesture detected, launching.");
launchEmergencyGesture = handleEmergencyGesture();
mUiEventLogger.log(GestureLauncherEvent.GESTURE_EMERGENCY_TAP_POWER);
}
//*/add open flash method
private static void writeFlashLightFile(boolean enable) {
File file = new File("/sys/kernel/flash_cur/flash_cur");
Writer writer = null;
try {
writer = new OutputStreamWriter(new FileOutputStream(file));
if (enable) {
writer.append("1");
} else {
writer.append("0");
}
} catch (FileNotFoundException e) {
} catch (IOException e) {
} finally {if (writer != null) {
try {
writer.close();
} catch (IOException e) {
}
}
}
}
//*/