BaseActivkty

public class BaseActivity extends Activity {    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        /**         * change style,hide status bar& navigation bar         */        requestWindowFeature(Window.FEATURE_NO_TITLE);        getWindow().getDecorView().setOnSystemUiVisibilityChangeListener(                new View.OnSystemUiVisibilityChangeListener() {                    @Override                    public void onSystemUiVisibilityChange(int visibility) {                        if ((visibility & (View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION)) == 0) {                            onWindowFocusChanged(true);                        }                    }                });        setContentView(R.layout.activity_main);        int SDK_VER = Integer.valueOf(android.os.Build.VERSION.SDK_INT);        if (SDK_VER == 15)            getWindow().getDecorView().setSystemUiVisibility(4);        else if (SDK_VER == 16 || SDK_VER == 17)            getWindow().getDecorView().setSystemUiVisibility(8);    }    /**     * change style,hide status bar& navigation bar     */    @Override    public void onWindowFocusChanged(boolean hasFocus) {        super.onWindowFocusChanged(hasFocus);        if (!hasFocus) {            // mBackDown = mHomeDown = false;        } else if (hasFocus) {            getWindow().getDecorView().setSystemUiVisibility(                    View.SYSTEM_UI_FLAG_LAYOUT_STABLE                            | View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION                            | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN                            | View.SYSTEM_UI_FLAG_HIDE_NAVIGATION                            | View.SYSTEM_UI_FLAG_FULLSCREEN                            | View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);        }    }//    /**//     * 拦截了返回按键逻辑//     *///    @Override//    public boolean dispatchKeyEvent(KeyEvent event) {//        if (event.getAction() == KeyEvent.ACTION_DOWN) {//            switch (event.getKeyCode()) {//            case KeyEvent.KEYCODE_BACK://                return true;//            case KeyEvent.KEYCODE_HOME://                return false;//            }//        } else if (event.getAction() == KeyEvent.ACTION_UP) {//            switch (event.getKeyCode()) {//            case KeyEvent.KEYCODE_BACK://                if (!event.isCanceled()) {//                }//                return true;//            case KeyEvent.KEYCODE_HOME://                if (!event.isCanceled()) {//                }//                return true;//            }//        }//        return super.dispatchKeyEvent(event);//    }        /**     * 点击返回按钮时调用的方法     * @param v     */    public void exitOnClick(View v) {        onBackPressed();    }    }