Android 实现全屏的Activity

import android.annotation.SuppressLint;import android.app.Activity;import android.app.AlertDialog;import android.os.Bundle;import android.os.Handler;import android.view.GestureDetector;import android.view.MotionEvent;import android.view.View;/** * @author Dawid Drozd *         <p> *         Please check before adding this fragment simply call *         isFragmentAvailable. *         <p> *         You must manually call onKeyDown and onWindowFocusChanged. */public abstract class FullScreenActivity extends Activity implements Runnable {    //全屏使用的flag    private static final int UI_FLAGS = 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;    GestureDetector mGesture = null;    @SuppressLint("NewApi")    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        mGesture = new GestureDetector(this, new GestureListener());        final View decorView = getWindow().getDecorView();        decorView.setOnSystemUiVisibilityChangeListener                (new View.OnSystemUiVisibilityChangeListener() {                    @Override                    public void onSystemUiVisibilityChange(int visibility) {//                        System.out.println("=====onSystemUiVisibilityChange=======");                        if ((visibility & View.SYSTEM_UI_FLAG_FULLSCREEN) == 0) {                            setImmersiveMode();//                            System.out.println("system bars are visible");                        }                    }                });    }    @Override    public boolean dispatchTouchEvent(MotionEvent ev) {        mGesture.onTouchEvent(ev);        return super.dispatchTouchEvent(ev);    }    @Override    protected void onResume() {        super.onResume();        setImmersiveMode();    }    @Override    public void onWindowFocusChanged(boolean hasFocus) {//        System.out.println("onWindowFocusChanged");        setImmersiveMode();        _handler.removeCallbacks(this);        _handler.postDelayed(this, 20);    }    @Override    public void onStop() {        _handler.removeCallbacks(this);        super.onStop();    }    @Override    public void run() {        setImmersiveMode();    }    @SuppressLint("NewApi")    public void setImmersiveMode() {        setImmersiveMode(this);    }    @SuppressLint("NewApi")    public void setImmersiveMode(Activity activity) {//        System.out.println("===============setImmersiveMode===============");        activity.getWindow().getDecorView().setSystemUiVisibility(UI_FLAGS);    }    private Handler _handler = new Handler() ;    private void addView() {//        System.out.println("============addView ============");        AlertDialog builder = new AlertDialog.Builder(this).create();        builder.setTitle("测试");        builder.show();        builder.dismiss();    }    class GestureListener extends GestureDetector.SimpleOnGestureListener {        @Override        public boolean onFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY) {            //判断导航栏是否弹出，这是在横屏情况下            System.out.println("========onFling========");            if (e1.getY() > e2.getY() && e1.getY() > 1480) {//从下往上滑                addView();            } else if (e1.getY() < e2.getY() && e1.getY() < 70) {  //从上往下滑                addView();            }            return super.onFling(e1, e2, velocityX, velocityY);        }    }    @Override    protected void onDestroy() {        super.onDestroy();    }}