假期学习记录9（Timer实现超简单的计时功能）

在layout文件中添加一个文本框

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical" >

    <TextView
        android:id="@+id/timerView"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_gravity="center_horizontal"
        android:textSize="60sp" />

</LinearLayout>

在对应的java文件中添加如下代码

package com.example.lastgps;

import android.os.Handler;
import android.os.Message;
import java.util.Timer;
import android.os.SystemClock;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.TextView;

import java.text.DecimalFormat;
import java.util.TimerTask;

public class time extends AppCompatActivity {
    private TextView timerView;
    private TextView runspeed;
    private long baseTimer;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_time);
        time.this.baseTimer = SystemClock.elapsedRealtime();
        timerView = (TextView) this.findViewById(R.id.timerView);
        final Handler startTimehandler = new Handler() {
            public void handleMessage(android.os.Message msg) {
                if (null != timerView) {
                    timerView.setText((String) msg.obj);
                }
            }
        };
        new Timer("开机计时器").scheduleAtFixedRate(new TimerTask() {
            @Override
            public void run() {
                int time = (int) ((SystemClock.elapsedRealtime() - time.this.baseTimer) / 1000);
                String hh = new DecimalFormat("00").format(time / 3600);
                String mm = new DecimalFormat("00").format(time % 3600 / 60);
                String ss = new DecimalFormat("00").format(time % 60);
                String timeFormat = new String(hh + ":" + mm + ":" + ss);
                Message msg = new Message();
                msg.obj = timeFormat;
                startTimehandler.sendMessage(msg);
            }

        }, 0, 1000L);

    }
}

运行结果如下