倒计时跳转

public class MainActivity extends AppCompatActivity {

    private int time=5;
    @SuppressLint("HandlerLeak")
    private Handler handler=new Handler() {
        @Override
        public void handleMessage(Message msg){
            switch (msg.what) {
                case 1:
                    time--;
                    shi.setText("" + time);
                if (time==0){
                    Intent intent = new Intent(MainActivity.this,ListActivity.class);
                    startActivity(intent);
                    finish();
                    break;

                }
            }
        }
    };
    private TextView shi;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);;

        setContentView(R.layout.activity_main);

        shi = findViewById(R.id.time);
        new Thread(){
            @Override
            public void run() {
                while(true) {
                    try {
                        Thread.sleep(1000);     // sleep 1000ms
                        Message message = new Message();
                        message.what = 1;
                        handler.sendMessage(message);
                    } catch (Exception e) {

                    }
                }
            }
        }.start();
    }
}