android4.0强制横屏竖屏

方法一：
android4.0/frameworks/base/services/java/com/android/server/wm/WindowManagerService.java

 int computeForcedAppOrientationLocked() {
        int req = getOrientationFromWindowsLocked();
        if (req == ActivityInfo.SCREEN_ORIENTATION_UNSPECIFIED) {
            req = getOrientationFromAppTokensLocked();
        }

        // req = ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE; //强制横屏0度

    // req = ActivityInfo.SCREEN_ORIENTATION_PORTRAIT; //强制竖屏左转90度

        return req;
    }


方法二：
android4.0/frameworks/base/services/surfaceflinger/SurfaceFlinger.cpp

void GraphicPlane::setDisplayHardware(DisplayHardware *hw)
{
    mHw = hw;

    // initialize the display orientation transform.

    // it's a constant that should come from the display driver.

    int displayOrientation = ISurfaceComposer::eOrientationDefault;
    char property[PROPERTY_VALUE_MAX];
    if (property_get("ro.sf.hwrotation", property, NULL) > 0) {
        //displayOrientation

        switch (atoi(property)) {
        case 0:
            displayOrientation = ISurfaceComposer::eOrientationDefault;
            break;
        case 90:
            displayOrientation = ISurfaceComposer::eOrientation90;
            break;
        case 180:
            displayOrientation = ISurfaceComposer::eOrientation180;
            break;
        case 270:
            displayOrientation = ISurfaceComposer::eOrientation270;
            break;
        }
    }
    /* 强制旋转90度 */
    displayOrientation = ISurfaceComposer::eOrientation90;

    const float w = hw->getWidth();
    const float h = hw->getHeight();
    GraphicPlane::orientationToTransfrom(displayOrientation, w, h,
            &mDisplayTransform);
}