Android4.1 Rotation 小结

1, 操作Android 辅助功能：

获取启动时的旋转方向：

-------> RotationPolicy.isRotationLocked() : packages/apps/Settings/src/com/android/settings/AccessibilitySettings.java

---->isRotationLocked() : frameworks/base/core/java/com/android/internal/view/RotationPolicy.java
----> Settings.System.ACCELEROMETER_ROTATION ----- 获取系统中的设置属性。

[java]
view plaincopy

61 /**
62 * Returns true if rotation lock is enabled.
63 */
64 public static boolean isRotationLocked(Context context) {
65 return Settings.System.getInt(context.getContentResolver(),
66 Settings.System.ACCELEROMETER_ROTATION, 0) == 0;
67 }



当 enable 或者 disable "Auto-rotate screen" 的时候

RotationPolicy.setRotationLockForAccessibility() : packages/apps/Settings/src/com/android/settings/AccessibilitySettings.java

setRotationLockForAccessibility() : frameworks/base/core/java/com/android/internal/view/RotationPolicy.java

[java]
view plaincopy

102 public static void setRotationLockForAccessibility(Context context, final boolean enabled) {
103 Settings.System.putInt(context.getContentResolver(),
104 Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY, enabled ? 1 : 0);
105
106 AsyncTask.execute(new Runnable() {
107 @Override
108 public void run() {
109 try {
110 IWindowManager wm = IWindowManager.Stub.asInterface(
111 ServiceManager.getService(Context.WINDOW_SERVICE));
112 if (enabled) {
113 wm.freezeRotation(Surface.ROTATION_0);
114 } else {
115 wm.thawRotation();
116 }
117 } catch (RemoteException exc) {
118 Log.w(TAG, "Unable to save auto-rotate setting");
119 }
120 }
121 });
122 }

如果enable： 调用WindowManagerService的freezeRotation()
否则调用wm.thawRotation() ----- 即WindowManagerService的thawRotation()

freezeRotation() ---------- frameworks/base/services/java/com/android/server/wm/WindowManagerService.java



[java]
view plaincopy

5663 /**
5664 * Freeze rotation changes. (Enable "rotation lock".)
5665 * Persists across reboots.
5666 * @param rotation The desired rotation to freeze to, or -1 to use the
5667 * current rotation.
5668 */
5669 public void freezeRotation(int rotation) {
5670 if (!checkCallingPermission(android.Manifest.permission.SET_ORIENTATION,
5671 "freezeRotation()")) {
5672 throw new SecurityException("Requires SET_ORIENTATION permission");
5673 }
5674 if (rotation < -1 || rotation > Surface.ROTATION_270) {
5675 throw new IllegalArgumentException("Rotation argument must be -1 or a valid "
5676 + "rotation constant.");
5677 }
5678
5679 if (DEBUG_ORIENTATION) Slog.v(TAG, "freezeRotation: mRotation=" + mRotation);
5680
5681 mPolicy.setUserRotationMode(WindowManagerPolicy.USER_ROTATION_LOCKED,
5682 rotation == -1 ? mRotation : rotation);
5683 updateRotationUnchecked(false, false);
5684

setUserRotationMode() ------frameworks/base/policy/src/com/android/internal/policy/impl/PhoneWindowManager.java
通过PhoneWindowManager.setUserRotationMode()去设置Settings.System相关的数据库值，在PhoneWindowManager中会有一个Observe去监听Settings.System的数值变化，如果有变动就去调用SettingsObserver.onChange()
.
updateRotationUnchecked ------- WindowManagerService.updateRotationUnchecked()

分析： thawRotation() ----------- 释放rotation ----- 无论什么时候都使能旋转：
调用 setUserRotationMode() -----mPolicy.setUserRotationMode(WindowManagerPolicy.USER_ROTATION_FREE, 777); // rot not used
分析setUserRotationMode :

[java]
view plaincopy

public void setUserRotationMode(int mode, int rot) {
ContentResolver res = mContext.getContentResolver();

// mUserRotationMode and mUserRotation will be assigned by the content observer
if (mode == WindowManagerPolicy.USER_ROTATION_LOCKED) {
Settings.System.putIntForUser(res,
Settings.System.USER_ROTATION,
rot,
UserHandle.USER_CURRENT);
Settings.System.putIntForUser(res,
Settings.System.ACCELEROMETER_ROTATION,
0,
UserHandle.USER_CURRENT);
} else {
Settings.System.putIntForUser(res,
Settings.System.ACCELEROMETER_ROTATION,
1,
UserHandle.USER_CURRENT);
}
}

---------------- 也就是说，如果在启动系统之前，调用thawrotation(), 就是强制地执行Settings.System.ACCELEROMETER_ROTATION；这样系统就会一直默认旋转。
以前遇到有一个问题：在系统启动时，强制打开系统旋转，这样在辅助功能的设置就会无效，正是这个原因。

[java]
view plaincopy

private final class BootCompletedReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
// At any given time accessories could be inserted
// one on the board, one on the dock and one on HDMI:
// observe three UEVENTs
init(); // set initial status
* try{
IWindowManager wm = IWindowManager.Stub.asInterface(
ServiceManager.getService(Context.WINDOW_SERVICE));
wm.thawRotation();
}catch(Exception e){

}*/
for (int i = 0; i < uEventInfo.size(); ++i) {
UEventInfo uei = uEventInfo.get(i);
startObserving("DEVPATH="+uei.getDevPath());
}
}
}