//第二次進入跳轉需要用到SharedPreferences記錄
SharedPreferences share;

//注意一定要進行這一步
share = getSharedPreferences("xiahongwu",MODE_PRIVATE);

Handler handler=new Handler(){
        @Override
        public void handleMessage(Message msg) {
            super.handleMessage(msg);
            time--;
            if(time<=0){

                startActivity(new Intent(MainActivity.this,Two.class));
                finish();
            }else{
                bt.setText(time+"");
                handler.sendEmptyMessageDelayed(1,1000);
            }
        }
    };

 

@Override
    protected void onDestroy() {
        if(handler!=null){
            handler.removeMessages(1);
            handler=null;
        }
        super.onDestroy();
    }

    handler.sendEmptyMessageDelayed(1,1000);

        
        boolean finish = share.getBoolean("finish", false);

        if(finish){
            startActivity(new Intent(MainActivity.this,Two.class));
            finish();
        }else{
            SharedPreferences.Editor edit=share.edit();
            edit.putBoolean("finish",true);
            edit.commit();
        }