android如何改变系统默认横竖屏方向

在android4.2sdk上，机器默认是横屏，横屏下camera位于机器右上角，安装竖屏APK后，APK旋转180度，需要将camera位置朝下使用。

这一点不符合消费者使用习惯，需要在竖屏APK的情况下，camera位置朝上。 强制改变屏幕启动的方向，我是改的out目录下的build.prop中的ro.sf.hwrotation=90//270，不过这样改，重力感应和camera，开机logo都要翻转方向

由此引出以下开机logo的修改，原生态的logo是ppm格式的，如何修改ppm格式呢，从网上查到的信息是通过代码

具体方法如下

1. pngtopnm logo_linux_clut224.png > logo_linux_clut224.pnm

2. pnmquant 224 logo_linux_clut224.pnm > logo_linux_clut224.pnm

3.pnmtoplainpnm logo_linux_clut224.pnm > logo_linux_clut224.ppm

要删除logo_linux_clut224.c  logo_linux_clut224.o 文件，重新编译内核，

注意编译完内核后，也要将上层编译下在打包，不然第一次烧录和recovery时，logo还会出现原来的现象

以下为转载部分

如何改变android默认的横竖屏，修改源码一个地方就可以了。

[java] view plaincopyprint?

1. public int rotationForOrientationLw(int orientation, int lastRotation,  
2.            boolean displayEnabled) {  
3.   
4.        if (mPortraitRotation < 0) {  
5.            // Initialize the rotation angles for each orientation once.  
6.            Display d = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))  
7.                    .getDefaultDisplay();  
8.            if (d.getWidth() > d.getHeight()) {  
9.                mPortraitRotation = Surface.ROTATION_90;  
10.                mLandscapeRotation = Surface.ROTATION_0;  
11.                mUpsideDownRotation = Surface.ROTATION_270;  
12.                mSeascapeRotation = Surface.ROTATION_180;  
13.            } else {  
14.                mPortraitRotation = Surface.ROTATION_0;  
15.                mLandscapeRotation = Surface.ROTATION_90;  
16.                mUpsideDownRotation = Surface.ROTATION_180;  
17.                mSeascapeRotation = Surface.ROTATION_270;  
18.            }  
19.        }  
20.   
21.     {  
22.         Log.i(TAG, "MediaPlayer.is not PlayingVideo");  
23.         synchronized (mLock) {  
24.             switch (orientation) {  
25.                 case ActivityInfo.SCREEN_ORIENTATION_PORTRAIT:  
26.                     //always return portrait if orientation set to portrait  
27.                     //return mPortraitRotation;  
28.                     return mUpsideDownRotation;  
29.                 case ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE:  
30.                     //always return landscape if orientation set to landscape  
31.                     return mLandscapeRotation;  
32.                 case ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT:  
33.                     //always return portrait if orientation set to portrait  
34.                     //return mUpsideDownRotation;  
35.                     return mPortraitRotation;  
36.                 case ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE:  
37.                     //always return seascape if orientation set to reverse landscape  
38.                     return mSeascapeRotation;  
39.                 case ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE:  
40.                     //return either landscape rotation based on the sensor  
41.                     mOrientationListener.setAllow180Rotation(  
42.                             isLandscapeOrSeascape(Surface.ROTATION_180));  
43.                     return getCurrentLandscapeRotation(lastRotation);  
44.                 case ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT:  
45.                     mOrientationListener.setAllow180Rotation(  
46.                             !isLandscapeOrSeascape(Surface.ROTATION_180));  
47.                     return getCurrentPortraitRotation(lastRotation);  
48.             }  
49.   
50.             mOrientationListener.setAllow180Rotation(  
51.                    orientation == ActivityInfo.SCREEN_ORIENTATION_FULL_SENSOR  
52.                    || orientation == ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);  
53.   
54.             // case for nosensor meaning ignore sensor and consider only lid  
55.             // or orientation sensor disabled  
56.             //or case.unspecified   
57.             if (mLidOpen) {  
58.                 return mLidOpenRotation;  
59.             } else if (mDockMode == Intent.EXTRA_DOCK_STATE_CAR && mCarDockRotation >= 0) {  
60.                 return mCarDockRotation;  
61.             } else if (mDockMode == Intent.EXTRA_DOCK_STATE_DESK && mDeskDockRotation >= 0) {  
62.                 return mDeskDockRotation;  
63.             } else {  
64.                 if (useSensorForOrientationLp(orientation)) {  
65.                     return mOrientationListener.getCurrentRotation(lastRotation);  
66.                 }  
67.                 return Surface.ROTATION_0;  
68.             }  
69.         }  
70. }  
71.    }  

 public int rotationForOrientationLw(int orientation, int lastRotation,            boolean displayEnabled) {        if (mPortraitRotation < 0) {            // Initialize the rotation angles for each orientation once.            Display d = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))                    .getDefaultDisplay();            if (d.getWidth() > d.getHeight()) {                mPortraitRotation = Surface.ROTATION_90;                mLandscapeRotation = Surface.ROTATION_0;                mUpsideDownRotation = Surface.ROTATION_270;                mSeascapeRotation = Surface.ROTATION_180;            } else {                mPortraitRotation = Surface.ROTATION_0;                mLandscapeRotation = Surface.ROTATION_90;                mUpsideDownRotation = Surface.ROTATION_180;                mSeascapeRotation = Surface.ROTATION_270;            }        }{Log.i(TAG, "MediaPlayer.is not PlayingVideo");        synchronized (mLock) {            switch (orientation) {                case ActivityInfo.SCREEN_ORIENTATION_PORTRAIT:                    //always return portrait if orientation set to portrait                    //return mPortraitRotation;                    return mUpsideDownRotation;                case ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE:                    //always return landscape if orientation set to landscape                    return mLandscapeRotation;                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_PORTRAIT:                    //always return portrait if orientation set to portrait                    //return mUpsideDownRotation;return mPortraitRotation;                case ActivityInfo.SCREEN_ORIENTATION_REVERSE_LANDSCAPE:                    //always return seascape if orientation set to reverse landscape                    return mSeascapeRotation;                case ActivityInfo.SCREEN_ORIENTATION_SENSOR_LANDSCAPE:                    //return either landscape rotation based on the sensor                    mOrientationListener.setAllow180Rotation(                            isLandscapeOrSeascape(Surface.ROTATION_180));                    return getCurrentLandscapeRotation(lastRotation);                case ActivityInfo.SCREEN_ORIENTATION_SENSOR_PORTRAIT:                    mOrientationListener.setAllow180Rotation(                            !isLandscapeOrSeascape(Surface.ROTATION_180));                    return getCurrentPortraitRotation(lastRotation);            }            mOrientationListener.setAllow180Rotation(                    orientation == ActivityInfo.SCREEN_ORIENTATION_FULL_SENSOR                    || orientation == ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED);            // case for nosensor meaning ignore sensor and consider only lid            // or orientation sensor disabled            //or case.unspecified            if (mLidOpen) {                return mLidOpenRotation;            } else if (mDockMode == Intent.EXTRA_DOCK_STATE_CAR && mCarDockRotation >= 0) {                return mCarDockRotation;            } else if (mDockMode == Intent.EXTRA_DOCK_STATE_DESK && mDeskDockRotation >= 0) {                return mDeskDockRotation;            } else {                if (useSensorForOrientationLp(orientation)) {                    return mOrientationListener.getCurrentRotation(lastRotation);                }                return Surface.ROTATION_0;            }        }}    }

修改上面倒数一行代码把return Surface.ROTATION_0改为你要的方向，记得这个要和上面的匹配，宽高不同，Surface.ROTATION_0也不同。因为代码开头就有

[java] view plaincopyprint?

1. if (mPortraitRotation < 0) {  
2.     // Initialize the rotation angles for each orientation once.  
3.     Display d = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))  
4.             .getDefaultDisplay();  
5.     if (d.getWidth() > d.getHeight()) {  
6.         mPortraitRotation = Surface.ROTATION_90;  
7.         mLandscapeRotation = Surface.ROTATION_0;  
8.         mUpsideDownRotation = Surface.ROTATION_270;  
9.         mSeascapeRotation = Surface.ROTATION_180;  
10.     } else {  
11.         mPortraitRotation = Surface.ROTATION_0;  
12.         mLandscapeRotation = Surface.ROTATION_90;  
13.         mUpsideDownRotation = Surface.ROTATION_180;  
14.         mSeascapeRotation = Surface.ROTATION_270;  
15.     }  
16. }  

        if (mPortraitRotation < 0) {            // Initialize the rotation angles for each orientation once.            Display d = ((WindowManager)mContext.getSystemService(Context.WINDOW_SERVICE))                    .getDefaultDisplay();            if (d.getWidth() > d.getHeight()) {                mPortraitRotation = Surface.ROTATION_90;                mLandscapeRotation = Surface.ROTATION_0;                mUpsideDownRotation = Surface.ROTATION_270;                mSeascapeRotation = Surface.ROTATION_180;            } else {                mPortraitRotation = Surface.ROTATION_0;                mLandscapeRotation = Surface.ROTATION_90;                mUpsideDownRotation = Surface.ROTATION_180;                mSeascapeRotation = Surface.ROTATION_270;            }        }