Android开发之初级开发_获取系统时间，并动态更新

MainActivity.java

import java.util.Calendar;

import android.app.Activity;
import android.os.Bundle;
import android.os.Handler;
import android.widget.TextView;

public class MainActivity extends Activity
{
    private TextView tv_time, tv_day, tv_week;

    protected void onCreate(Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        tv_time = (TextView) findViewById(R.id.time);
        tv_day = (TextView) findViewById(R.id.day);
        tv_week = (TextView) findViewById(R.id.week);
        handler.post(runnable);
    }

    private Handler handler = new Handler();
    
    private Runnable runnable = new Runnable()
    {

        public void run()
        {
            gettime();
            handler.postDelayed(this, 1000);
        }
    };

    public void gettime()
    {
        Calendar calendar = Calendar.getInstance();
        // 获取年,月，日；
        String year = calendar.get(Calendar.YEAR) + "";
        int month = calendar.get((Calendar.MONTH)) + 1;
        String day = calendar.get(Calendar.DAY_OF_MONTH) + "";
        String yearString = year + "/" + (month) + "/" + day;
        tv_day.setText(yearString);
        // 获取系统时间
        int hour = calendar.get(Calendar.HOUR_OF_DAY);
        String minute = calendar.get(Calendar.MINUTE) + "";
        int miao = calendar.get(Calendar.SECOND);
        String timeString = hour + ":" + minute + ":" + miao;
        tv_time.setText(timeString);
        // 获取系统星期几
        int week = calendar.get(Calendar.DAY_OF_WEEK);
        String weekString = null;
        switch (week)
        {
        case 1:
            weekString = "天";
            break;
        case 2:
            weekString = "一";
            break;
        case 3:
            weekString = "二";
            break;
        case 4:
            weekString = "三";
            break;
        case 5:
            weekString = "四";
            break;
        case 6:
            weekString = "五";
            break;
        case 7:
            weekString = "六";
            break;
        }
        tv_week.setText("星期" + weekString);
    }

}

布局文件：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="horizontal" >

    <TextView
        android:id="@+id/time"
        android:layout_width="80dp"
        android:layout_height="60dp"
        android:gravity="center"
        android:text="时间" />

    <TextView
        android:layout_width="1dp"
        android:layout_height="60dp"
        android:text="|"
        android:textColor="#060" />

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical" >

        <TextView
            android:id="@+id/day"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="日期" />

        <TextView
            android:id="@+id/week"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="星期天" />
    </LinearLayout>

</LinearLayout>