实现时钟和定时器

一、修改布局文件

<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:paddingLeft="@dimen/activity_horizontal_margin"
    android:orientation="vertical"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity">
    <AnalogClock
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
    <TextClock
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="10pt"
        android:textColor="#f0f"
        android:format12Hour="yyyy年MM月dd日 H:mma EEEE"
        />
    <Chronometer
        android:id="@+id/test"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />


    <Button
        android:id="@+id/start"
        android:text="Start"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content" />
</LinearLayout>

二、修改MainActivity文件

package com.example.yxp.httpservice;

import java.io.IOException;
import java.io.InputStream;
import java.net.ServerSocket;
import java.net.Socket;

import android.os.AsyncTask;
import android.os.Bundle;
import android.app.Activity;
import android.os.SystemClock;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.Chronometer;


public class MainActivity extends Activity {



    Chronometer ch;
    Button start;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ch = (Chronometer) findViewById(R.id.test);
        start = (Button) findViewById(R.id.start);
        start.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                ch.setBase(SystemClock.elapsedRealtime());
                ch.start();
                start.setEnabled(false);
            }
        });


        ch.setOnChronometerTickListener(new Chronometer.OnChronometerTickListener() {
            @Override
            public void onChronometerTick(Chronometer chronometer) {
                if(SystemClock.elapsedRealtime() - ch.getBase()>20*1000)
                 {
                    ch.stop();
                    start.setEnabled(true);

                }
            }
        });

    }


}

三、效果