Android计时器Chronometer-android学习之旅（二十一）

Chronometer简介

Chronometer和DigitalColok都继承与TextView，但是Chronometer不是显示的当前时间，而是从某个时间开始又过去了多少时间，是一个时间差。

Chronometer的属性

记时20秒的实例

package peng.liu.testview;

import android.app.Activity;
import android.os.Bundle;
import android.os.SystemClock;
import android.view.View;
import android.widget.Button;
import android.widget.Chronometer;

public class MainActivity extends Activity {
    private Button strat;
    private Chronometer chronometer;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        chronometer = (Chronometer) findViewById(R.id.chronometer);
        strat = (Button) findViewById(R.id.start);
        strat.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                chronometer.setBase(SystemClock.elapsedRealtime());
                chronometer.start();
                strat.setEnabled(false);
            }
        });
        chronometer.setOnChronometerTickListener(new Chronometer.OnChronometerTickListener() {
            @Override
            public void onChronometerTick(Chronometer chronometer) {
                if (SystemClock.elapsedRealtime()-chronometer.getBase()>20*1000){
                    chronometer.stop();
                    strat.setEnabled(true);
                }
            }
        });
    }
}

<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:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    tools:context=".MainActivity"
    android:orientation="vertical">
  <Chronometer
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:id="@+id/chronometer"/>
    <Button
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/start"
        android:text="start"/>

</LinearLayout>