Android 横竖屏切换

1.Activity.setRequestedOrientation (int requestedOrientation)。

2.getResources().getConfiguration().orientation；

private int getCurentOrientation() {
    Display display  = ((WindowManager) getSystemService(WINDOW_SERVICE)).getDefaultDisplay();
    int rotation = display.getRotation();
    boolean isWide = display.getWidth() >= display.getHeight();
    switch (rotation) {
    case Surface.ROTATION_0:
        return isWide ? ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE
                : ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
    case Surface.ROTATION_90:
        return isWide ? ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE
                : ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;
    case Surface.ROTATION_180:
        return isWide ? ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE
                : ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT;
    case Surface.ROTATION_270:
        return isWide ? ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE
                : ActivityInfo.SCREEN_ORIENTATION_PORTRAIT;
    }
    return -1;
}

3.Settings.java

public final class Settings {
...
 /**
         * Control whether the accelerometer will be used to change screen
         * orientation.  If 0, it will not be used unless explicitly requested
         * by the application; if 1, it will be used by default unless explicitly
         * disabled by the application.
         */
        public static final String ACCELEROMETER_ROTATION = "accelerometer_rotation";

DisplaySettings.java

@Override
    public boolean onPreferenceTreeClick(PreferenceScreen preferenceScreen, Preference preference) {
        if (preference == mAccelerometer) {
            RotationPolicy.setRotationLockForAccessibility(
                    getActivity(), !mAccelerometer.isChecked());
        ...

RotationPolicy.java

/**
     * Enables or disables rotation lock.
     *
     * Should be used by the rotation lock toggle.
     */
    public static void setRotationLock(Context context, final boolean enabled) {
        Settings.System.putIntForUser(context.getContentResolver(),
                Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY, 0,
                UserHandle.USER_CURRENT);

        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
                    if (enabled) {
                        wm.freezeRotation(-1);
                    } else {
                        wm.thawRotation();
                    }
                } catch (RemoteException exc) {
                    Log.w(TAG, "Unable to save auto-rotate setting");
                }
            }
        });
    }

/**
     * Enables or disables rotation lock and adjusts whether the rotation lock toggle
     * should be hidden for accessibility purposes.
     *
     * Should be used by Display settings and Accessibility settings.
     */
    public static void setRotationLockForAccessibility(Context context, final boolean enabled) {
        Settings.System.putIntForUser(context.getContentResolver(),
                Settings.System.HIDE_ROTATION_LOCK_TOGGLE_FOR_ACCESSIBILITY, enabled ? 1 : 0,
                        UserHandle.USER_CURRENT);

        AsyncTask.execute(new Runnable() {
            @Override
            public void run() {
                try {
                    IWindowManager wm = WindowManagerGlobal.getWindowManagerService();
                    if (enabled) {
                        wm.freezeRotation(Surface.ROTATION_0);
                    } else {
                        wm.thawRotation();
                    }
                } catch (RemoteException exc) {
                    Log.w(TAG, "Unable to save auto-rotate setting");
                }
            }
        });
    }

WindowManagerService.java

 /**
     * Freeze rotation changes.  (Enable "rotation lock".)
     * Persists across reboots.
     * @param rotation The desired rotation to freeze to, or -1 to use the
     * current rotation.
     */
    @Override
    public void freezeRotation(int rotation) {
        if (!checkCallingPermission(android.Manifest.permission.SET_ORIENTATION,
                "freezeRotation()")) {
            throw new SecurityException("Requires SET_ORIENTATION permission");
        }
        if (rotation < -1 || rotation > Surface.ROTATION_270) {
            throw new IllegalArgumentException("Rotation argument must be -1 or a valid "
                    + "rotation constant.");
        }

        if (DEBUG_ORIENTATION) Slog.v(TAG, "freezeRotation: mRotation=" + mRotation);

        long origId = Binder.clearCallingIdentity();
        try {
            mPolicy.setUserRotationMode(WindowManagerPolicy.USER_ROTATION_LOCKED,
                    rotation == -1 ? mRotation : rotation);
        } finally {
            Binder.restoreCallingIdentity(origId);
        }

        updateRotationUnchecked(false, false);
    }

    /**
     * Thaw rotation changes.  (Disable "rotation lock".)
     * Persists across reboots.
     */
    @Override
    public void thawRotation() {
        if (!checkCallingPermission(android.Manifest.permission.SET_ORIENTATION,
                "thawRotation()")) {
            throw new SecurityException("Requires SET_ORIENTATION permission");
        }

        if (DEBUG_ORIENTATION) Slog.v(TAG, "thawRotation: mRotation=" + mRotation);

        long origId = Binder.clearCallingIdentity();
        try {
            mPolicy.setUserRotationMode(WindowManagerPolicy.USER_ROTATION_FREE,
                    777); // rot not used
        } finally {
            Binder.restoreCallingIdentity(origId);
        }

        updateRotationUnchecked(false, false);
    }

WindowManagerGlobal.java

public final class WindowManagerGlobal {
...
public static IWindowManager getWindowManagerService() {
        synchronized (WindowManagerGlobal.class) {
            if (sWindowManagerService == null) {
                sWindowManagerService = IWindowManager.Stub.asInterface(
                        ServiceManager.getService("window"));
            }
            return sWindowManagerService;
        }
    }

老的Android系统过程间的转换可参考Android4.0 状态栏添加屏幕锁定按钮和Android4.1 关于Rotation相关的Configuration整体分析。

try {
		IWindowManager mWindowManagerService = IWindowManager.Stub.asInterface(ServiceManager.getService("window"));
		classType = Class.forName("android.view.IWindowManager");
		Method freezeRotation = classType.getDeclaredMethod("freezeRotation",new Class[]{Integer.TYPE});
		freezeRotation,setAccessible(true);
		freezeRotation.invoke(mWindowManagerService,new Object[]{ Surface.ROTATION_0 });

		Method thawRotation = classType.getDeclaredMethod("thawRotation",null);
		thawRotation,setAccessible(true);
		freezeRotation.invoke(mWindowManagerService,null);
	} catch (NoSuchMethodException x) {
	} catch (IllegalAccessException x) {
	} catch (InvocationTargetException x) {
	} catch (IllegalArgumentException x) {
	} catch (NoSuchFieldException x) {
	}

【注】Java反射请参考The Reflection API

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