需求：某个app横屏显示不全，需要强制它竖屏显示，强制APP旋转优先级＞系统方向优先级

如果系统没有强制横竖屏，一般都是默认应用本身的方向设置！

./frameworks/base/services/core/java/com/android/server/wm/DisplayRotation.java

rotationForOrientation()和updateOrientation() 来负责修改当前app的显示方向

@Surface.Rotation
int rotationForOrientation(@ScreenOrientation int orientation,
        @Surface.Rotation int lastRotation) {
        
        ...
        
        } else {
            // No overriding preference.
            // We will do exactly what the application asked us to do.
            preferredRotation = -1;
        }
        
        String rot = SystemProperties.get("persist.sys.app.rotation", "middle_port");
        //add start 动态控制
        if (rot.equals("force_landscape_customer")) {
            orientation = mLandscapeRotation;//强制Activity显示横
        } else if (rot.equals("force_portrait_customer")) {
            orientation = mPortraitRotation;//强制Activity显示竖
        }
        //add end
        if (rot.equals("force_land") && "box".equals(SystemProperties.get("ro.target.product"))) {
            Slog.v(TAG, "asx force_land :" + mLandscapeRotation);
            return mLandscapeRotation;
        }
        //根据orientation 来显示应用方向
        switch (orientation) {
            case ActivityInfo.SCREEN_ORIENTATION_PORTRAIT://如果是竖屏
                // Return portrait unless overridden.
                if (isAnyPortrait(preferredRotation)) {
                    return preferredRotation;
                }
                /*如果不要动态根据参数修改,前面的拦截add start 部分注释掉,然后直接在switch里面改,把return mPortraitRotation;
                改成 return mLandscapeRotation;或者return Surface.ROTATION_90 */
                return mPortraitRotation;

            case ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE://如果是横屏
                // Return landscape unless overridden.
                if (isLandscapeOrSeascape(preferredRotation)) {
                    return preferredRotation;
                }
                return mLandscapeRotation;

            case ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT://如果是屏幕方向是竖屏反转：
                // Return reverse portrait unless overridden.
                if (isAnyPortrait(preferredRotation)) {
                    return preferredRotation;
                }
                return mUpsideDownRotation;
                
            ...    
         
}


boolean updateOrientation(@ScreenOrientation int newOrientation, boolean forceUpdate) {
        if (newOrientation == mLastOrientation && !forceUpdate) {
            return false;
        }
        mLastOrientation = newOrientation;
        if (newOrientation != mCurrentAppOrientation) {
            mCurrentAppOrientation = newOrientation;
            String rot = SystemProperties.get("persist.sys.app.rotation", "middle_port");//系统给了一个原生的,就用这个,如果系统没有给,那就自己创建
            //add start
            if (rot.equals("force_landscape_customer")) {
                mCurrentAppOrientation = ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE;
            } else if (rot.equals("force_portrait_customer")) {
                mCurrentAppOrientation = ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT;
            }
            //add end
            if (rot.equals("force_land") && "box".equals(SystemProperties.get("ro.target.product")))
                mCurrentAppOrientation = ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE;
            if (isDefaultDisplay) {
                updateOrientationListenerLw();
            }
        }
        return updateRotationUnchecked(forceUpdate);
    }
    
    
 2.1 切换横屏时SystemUI导航栏固定在桌面右侧而不是底部
 R.bool.config_navBarCanMove 是否固定跟这个变量有关系，不跟随旋转false  跟随旋转true
 +++ b/frameworks/base/services/core/java/com/android/server/wm/DisplayPolicy.java
@@ -2895,9 +2895,10 @@ public class DisplayPolicy {
 
     void updateConfigurationAndScreenSizeDependentBehaviors() {
         final Resources res = getCurrentUserResources();
-        mNavigationBarCanMove =
-                mDisplayContent.mBaseDisplayWidth != mDisplayContent.mBaseDisplayHeight
-                        && res.getBoolean(R.bool.config_navBarCanMove);
+        //mNavigationBarCanMove =
+        //        mDisplayContent.mBaseDisplayWidth != mDisplayContent.mBaseDisplayHeight
+        //                && res.getBoolean(R.bool.config_navBarCanMove);
+        mNavigationBarCanMove = false;
         mDisplayContent.getDisplayRotation().updateUserDependentConfiguration(res);
     }

强制APP横竖屏方向_android 强制竖屏-

Android 11 系统默认横屏显示_高通android11默认横屏