Handler倒计时跳转

在布局里设置TextView控件
具体实现步骤

import android.content.Intent;
import android.content.SharedPreferences;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import jiaoyibo.bawei.com.yuekao1.base.BaseActivity;

public class MainActivity extends BaseActivity {

    private TextView time;
    //设置时长
    private int i =5;
    private SharedPreferences sp;
    private Handler handler = new Handler(){
        //handler延迟发送信息并将秒数赋值给TextView
        @Override
        public void handleMessage(Message msg) {
            if(msg.what==0){
                i--;
                if(i==0){
                    //获取值
                    sp.edit().putBoolean("isfirst",false).commit();
                    Intent intent = new Intent(MainActivity.this, ShowActivity.class);
                    startActivity(intent);
                    finish();
                }
                time.setText(i+"S");
                //再次发送信息
                handler.sendEmptyMessageDelayed(0,1000);
            }
        }
    };
    @Override
    protected int getLayoutId() {
        return R.layout.activity_main;
    }

    @Override
    protected void initView() {
        //找控件
        time = findViewById(R.id.time);

    }
    @Override
    protected void initData() {
        //得到SharedPreferences通过键值对找到里边的boolean
        sp = getSharedPreferences("config", MODE_PRIVATE);
        //创建并传值
        boolean isfirst = sp.getBoolean("isfirst", true);
        //如果为true就证明进入过该页面，直接跳转下一个页面
        if(isfirst){
            //发送信息
            handler.sendEmptyMessageDelayed(0,1000);
        }else{
            Intent intent = new Intent(MainActivity.this, ShowActivity.class);
            startActivity(intent);
            finish();
        }
    }
}