Android Learning notes-timer implementation

Write code based on Android crazy handouts and summarize the written code in your blog. The function is simple: A simple timer, click the Start button will start the timer, when the time to 20 seconds will automatically stop the timing.

The interface is as follows:

Interface code:

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<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"               android:orientation="vertical"               android:layout_width="fill_parent"               android:layout_height="fill_parent"               android:gravity="center_horizontal"         >     <Chronometer             android:id="@+id/test"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:textSize="12pt"             android:textColor="#ffff0000"             />     <Button             android:id="@+id/start"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:text="启动"             /> </LinearLayout>

Activity.java

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package com.example.test3_3_12;import android.app.Activity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.Chronometer; import android.os.SystemClock;public class MyActivity extends Activity {     Button start;     Chronometer ch;     /**      * Called when the activity is first created.      */     @Override     public void onCreate(Bundle savedInstanceState) {         super.onCreate(savedInstanceState);         setContentView(R.layout.main);         ch=(Chronometer)findViewById(R.id.test);         start=(Button) findViewById(R.id.start);         start.setOnClickListener(new View.OnClickListener() {             @Override             public void onClick(View view) {                 //设置开始时间                 ch.setBase(SystemClock.elapsedRealtime());                 //启动计时器                 ch.start();                 start.setEnabled(false);             }         });         //为Chronometer绑定事件监听器         ch.setOnChronometerTickListener(new Chronometer.OnChronometerTickListener() {             @Override             public void onChronometerTick(Chronometer chronometer) {                 //如果从开始计时到现在超过了20s                 if(SystemClock.elapsedRealtime()-ch.getBase()>20*1000)                 {                     ch.stop();                     start.setEnabled(true);                }             }         });    } }

One of the timer components used here is mainly: chronometer, which is inherited TextView, so it can display a paragraph, but this text can only display the time, and is not the current time, but a time period (difference).

Chronometer supports a common approach:

SetBase (long Base): Sets the start time of the timer. SetBase (Systemclock.elapsedrealtime ()) Set the start time to the current time of the system, Systemclock need to import Android.os.SystemClock header file.

SetFormat (String format): Sets the format of the display time.

Start (): Start timing.

Stop (): Stop timing.

Setonchronometerticklistener (Chronometer.onchronometerticklistener Listener) is the timer's event listener when a timer change is triggered by that listener.