TextView显示系统时间(时钟功能带秒针变化

我们开启一个线程，线程每隔一秒发送一次消息，我们在消息中更新TextView上显示的时间就ok了。

首先我们在布局文件中放一个TextView用来显示时间，如下所示：

 
<?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:background="@android:color/white">
 
  <TextView
 
      android:id="@+id/mytime"
 
      android:layout_width="match_parent"
 
      android:layout_height="match_parent"
 
      android:gravity="center"
 
      android:textColor="@android:color/black"
 
      android:textSize="36sp"/>
 
</LinearLayout>

之后我们写一个线程，线程里面无限循环，每隔一秒发送一个消息,其中由Handler来处理显示的结果：

复制代码代码如下:

 
public class TimeThread extends Thread {
 
        @Override
 
        public void run () {
 
            do {
 
                try {
 
                    Thread.sleep(1000);
 
                    Message msg = new Message();
 
                    msg.what = msgKey1;
 
                    mHandler.sendMessage(msg);
 
                }
 
                catch (InterruptedException e) {
 
                    e.printStackTrace();
 
                }
 
            } while(true);
 
        }
 
    }

private Handler mHandler = new Handler() {
        @Override
        public void handleMessage (Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case msgKey1:
                    long sysTime = System.currentTimeMillis();
                    CharSequence sysTimeStr = DateFormat.format("hh:mm:ss", sysTime);
                    mTime.setText(sysTimeStr);
                    break;

                default:
                    break;
            }
        }
    };

之后我们可以在Activity的onCreate方法中开启这个线程，这时我们可以看到一个数字时钟了：

复制代码代码如下:

 
public void onCreate(Bundle savedInstanceState) {
 
         super.onCreate(savedInstanceState);
 
         setContentView(R.layout.time);
 
         mTime = (TextView) findViewById(R.id.mytime);
 
         new TimeThread().start();
 
     }

整个Activity的代码：

复制代码代码如下:

package com.fermax.test;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.text.format.DateFormat;
import android.widget.TextView;

public class TestActivity extends Activity {

    private static final int msgKey1 = 1;
    private TextView mTime;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.time);
        mTime = (TextView) findViewById(R.id.mytime);
        new TimeThread().start();
    }

    public class TimeThread extends Thread {
        @Override
        public void run () {
            do {
                try {
                    Thread.sleep(1000);
                    Message msg = new Message();
                    msg.what = msgKey1;
                    mHandler.sendMessage(msg);
                }
                catch (InterruptedException e) {
                    e.printStackTrace();
                }
            } while(true);
        }
    }

    private Handler mHandler = new Handler() {
        @Override
        public void handleMessage (Message msg) {
            super.handleMessage(msg);
            switch (msg.what) {
                case msgKey1:
                    long sysTime = System.currentTimeMillis();
                    CharSequence sysTimeStr = DateFormat.format("hh:mm:ss", sysTime);
                    mTime.setText(sysTimeStr);
                    break;

                default:
                    break;
            }
        }
    };
}

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TextView显示系统时间(时钟功能带秒针变化

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