Android Studio之显示本地时间

•效果展示图

•代码

1 package com.example.table;
2
3 import android.os.Bundle;
4 import android.os.Handler;
5 import android.os.Message;
6 import android.widget.Button;
7 import android.widget.TextView;
8
9 import androidx.appcompat.app.AppCompatActivity;
10
11 import java.text.SimpleDateFormat;
12 import java.util.Date;
13
14 public class ShowTimeActivity extends AppCompatActivity {
15
16 private Thread thread;
17 private Handler handler; //异步消息处理器
18 private TextView tvTime;
19 private SimpleDateFormat sdf;
20 private boolean runing;
21 private TextView Tv1;
22 private Button Btn1;
23
24 @Override
25 protected void onCreate(Bundle savedInstanceState) {
26 super.onCreate(savedInstanceState);
27 setContentView(R.layout.activity_show_time);
28
29 tvTime = findViewById(R.id.tv_1);
30 sdf = new SimpleDateFormat("hh:mm:ss");
31 tvTime.setText(sdf.format(new Date()));
32
33 //创建消息处理器 接受子线程发送的消息 根据它做出处理，跟新主界面的值
34 handler = new Handler(){
35 @Override
36 public void handleMessage(Message msg) {
37 super.handleMessage(msg);
38 if(msg.what == 1){
39 tvTime.setText(sdf.format(new Date()));
40 }
41 }
42 };
43
44 thread = new Thread(new Runnable() {
45 @Override
46 public void run() {
47 while (true){
48 //让线程 发送消息
49 handler.sendEmptyMessage(1);
50 //让线程 睡眠500毫秒
51 try {
52 Thread.sleep(500);
53 } catch (InterruptedException e) {
54 e.printStackTrace();
55 }
56 }
57 }
58 });
59 //启动线程
60 thread.start();
61 }
62 }

ShwoTimeActivity.java

1 <?xml version="1.0" encoding="utf-8"?>
2 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
3 xmlns:app="http://schemas.android.com/apk/res-auto"
4 xmlns:tools="http://schemas.android.com/tools"
5 android:layout_width="match_parent"
6 android:layout_height="match_parent"
7 tools:context=".ShowTimeActivity"
8 android:background="#0288D1">
9
10 <TextView
11 android:id="@+id/tv_1"
12 android:layout_width="wrap_content"
13 android:layout_height="wrap_content"
14 android:layout_centerInParent="true"
15 android:textSize="30sp"/>
16
17 </RelativeLayout>

activity_show_time.xml