//activity_start.class

package com.example.yuanann.myregietration;

import android.content.Intent;
import android.os.Handler;
import android.os.Message;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import androidx.fragment.app.Fragment;
import androidx.viewpager.widget.PagerAdapter;
import androidx.viewpager.widget.ViewPager;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;

import java.util.Timer;          //在Java语言中实现定时功能，可以使用Timer以及TimerTask实现，jdk1.5之后也可以使用ScheduledExcecutorService 实现.

import java.util.TimerTask;

public class Activity_Start extends AppCompatActivity {

    private Button jumps;
    private int recLen = 5;

    Timer timer = new Timer();
    private final long SPLASH_LENGTH = 3000;
    //Handler handler = new Handler();
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_start);

        jumps=(Button)findViewById(R.id.jumps);
        timer.schedule(task, 1000, 1000);

        jumps.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Intent intent = new Intent(activity_start.this, activity_main.class);
                startActivity(intent);
                timer.cancel();
                finish();
            }
        });

    }

    final Handler handler2 = new Handler(){    //传递Message。用于接受子线程发送的数据, 并用此数据配合主线程更新UI。
        @Override
        public void handleMessage(Message msg){
            switch (msg.what) {
                case 1:
                    jumps.setText(recLen + "s跳过");
                    if(recLen == 0){
                        timer.cancel();
                        Intent intent = new Intent(activity_start.this, activity_main.class);
                        startActivity(intent);
                        finish();
                    }
            }
        }
    };

    TimerTask task = new TimerTask() {     //TimerTask类用来实现由Timer安排的一次或者重复执行的某一个任务。
        @Override
        public void run() {
            recLen--;
            Message message = new Message();
            message.what = 1;
            handler2.sendMessage(message);
        }
    };

}