Day03。。通知，双击退出

进度条监听

@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
public void ccclick(View view) {
    //设置通知
    final NotificationManager systemService = (NotificationManager) getSystemService(Context.NOTIFICATION_SERVICE);
    final Notification.Builder builder = new Notification.Builder(this);
    //设置点击删除
    builder.setAutoCancel(true);
    builder.setSmallIcon(R.mipmap.ic_launcher);
    builder.setContentTitle("Shaw");
    //设置如同QQ一样的提示通知
    builder.setPriority(Notification.PRIORITY_MAX);
    builder.setDefaults(Notification.DEFAULT_ALL);
    //设置进度条
    final Timer timer = new Timer();
    //开启timer监听
    timer.schedule(new TimerTask() {
        int process;
        //进入子线程
        @Override
        public void run() {
            builder.setContentText("正在下载" + process);
            //设置最大值
            builder.setProgress(100, process, false);
            //每次调用加十
            process += 10;
            //开启设置
            Notification build = builder.build();
            systemService.notify(123, build);
            //判断如果下载完成
            if (process == 100) {
                //进行模糊安装
                builder.setContentText("正在安装");
                //安装模糊
                builder.setProgress(0, 0, true);
                //设置开启通知
                systemService.notify(123, builder.build());
                try {
                    //暂停五秒，设置模糊监听
                    Thread.sleep(5000);//模拟安装过程
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                //3.安装完成
                systemService.cancel(123);//取消置顶的通知
                timer.cancel();
            }
        }
    }, 0, 1000);
    //设置开启通知
    systemService.notify(123, builder.build());
}

双击关闭

@Override
//开启keydown监听
public boolean onKeyDown(int keyCode, KeyEvent event) {
    //判断是否是退出
    if (keyCode == KeyEvent.KEYCODE_BACK) {
        //判断是否两次点击在2秒之内
        if (System.currentTimeMillis() - ettime > 2000) {
            Toast.makeText(this, "再按一次退出", Toast.LENGTH_SHORT).show();
            ettime = System.currentTimeMillis();
            return true;
        }
        //结束当前activity
        else {
            finish();
        }
    }
    return super.onKeyDown(keyCode, event);
}