解决安卓全屏问题：关键在于如何隐藏状态栏

    requestWindowFeature(Window.FEATURE_NO_TITLE);
    getWindow().addFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN);
    getWindow().addFlags(WindowManager.LayoutParams.TYPE_STATUS_BAR);
    setContentView(R.layout.screen_av);
    getWindow().setLayout(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT);

        <meta-data android:name="android.max_aspect" android:value="2.1" />
        <activity android:name="ScreenAV"
            android:configChanges="orientation|keyboardHidden|screenSize"
            android:theme="@android:style/Theme.NoTitleBar.Fullscreen"
            >
        </activity>

getWindow().getDecorView().setSystemUiVisibility(View.SYSTEM_UI_FLAG_FULLSCREEN);
// View.SYSTEM_UI_FLAG_LAYOUT_STABLE：布局变化时状态栏位置会显示出来。