不要停止計時器，當我改變活動

Question

例如：在Activty AI有Chronometer，我點擊播放開始它，當它到達00:00:10我決定去Activity B.在返回到A之前，我會繼續等待30秒。我會發現計時器暫停仍顯示00:00:10，但我想看到它仍在運行，然後在00:00:40。我怎樣才能做到這一點？我如何避免在Activity的變化中暫停計時器？

Answer 1

（根據針對Get time of chronometer widget給出，其中代碼，並加入額外的活性的答案）

主要活動：

package com.so.chilledrat.chronoexample; 

import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.os.SystemClock; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.Chronometer; 
import android.widget.LinearLayout; 
import android.widget.Toast; 

public class ChronoExampleActivity extends Activity { 
    Chronometer mChronometer; 

    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 

     LinearLayout layout = new LinearLayout(this); 
     layout.setOrientation(LinearLayout.VERTICAL); 

     mChronometer = new Chronometer(this); 
     layout.addView(mChronometer); 

     Button startButton = new Button(this); 
     startButton.setText("Start"); 
     startButton.setOnClickListener(mStartListener); 
     layout.addView(startButton); 

     Button stopButton = new Button(this); 
     stopButton.setText("Stop"); 
     stopButton.setOnClickListener(mStopListener); 
     layout.addView(stopButton); 

     Button resetButton = new Button(this); 
     resetButton.setText("Reset"); 
     resetButton.setOnClickListener(mResetListener); 
     layout.addView(resetButton); 

     Button switchButton = new Button(this); 
     switchButton.setText("Switch Activity"); 
     switchButton.setOnClickListener(mSwitchListener); 
     layout.addView(switchButton); 

     setContentView(layout); 
    } 

    private void showElapsedTime() { 
     long elapsedMillis = SystemClock.elapsedRealtime() - mChronometer.getBase(); 
     Toast.makeText(this, "Elapsed milliseconds: " + elapsedMillis, Toast.LENGTH_SHORT).show(); 
    } 

    View.OnClickListener mStartListener = new OnClickListener() { 
     public void onClick(View v) { 
      mChronometer.start(); 
      showElapsedTime(); 
     } 
    }; 

    View.OnClickListener mStopListener = new OnClickListener() { 
     public void onClick(View v) { 
      mChronometer.stop(); 
      showElapsedTime(); 
     } 
    }; 

    View.OnClickListener mResetListener = new OnClickListener() { 
     public void onClick(View v) { 
      mChronometer.setBase(SystemClock.elapsedRealtime()); 
      showElapsedTime(); 
     } 
    }; 

    View.OnClickListener mSwitchListener = new OnClickListener() { 
     @Override 
     public void onClick(View v) { 
      Intent myIntent = new Intent(ChronoExampleActivity.this.getBaseContext(), OtherActivity.class); 
      startActivityForResult(myIntent, 0); 
     } 
    }; 
} 

的其他活動，切換到：

package com.so.chilledrat.chronoexample; 

import android.app.Activity; 
import android.os.Bundle; 
import android.view.View; 
import android.view.View.OnClickListener; 
import android.widget.Button; 
import android.widget.LinearLayout; 

public class OtherActivity extends Activity { 
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
     super.onCreate(savedInstanceState); 
     LinearLayout layout = new LinearLayout(this); 
     layout.setOrientation(LinearLayout.VERTICAL); 

     Button switchButton = new Button(this); 
     switchButton.setText("Switch Back"); 
     switchButton.setOnClickListener(mSwitchListener); 
     layout.addView(switchButton); 

     setContentView(layout); 
    } 

    View.OnClickListener mSwitchListener = new OnClickListener() { 

     @Override 
     public void onClick(View v) { 
      // Intent myIntent = new Intent(OtherActivity.this.getBaseContext(), 
      // ChronoExampleActivity.class); 
      // startActivityForResult(myIntent, 0); 
      finish(); 
     } 

    }; 
} 

最後清單：

<?xml version="1.0" encoding="utf-8"?> 
<manifest xmlns:android="http://schemas.android.com/apk/res/android" 
    package="com.so.chilledrat.chronoexample" 
    android:versionCode="1" 
    android:versionName="1.0" > 

    <uses-sdk android:minSdkVersion="7" android:targetSdkVersion="7" /> 

    <application 
     android:icon="@drawable/ic_launcher" 
     android:label="@string/app_name" > 
     <activity 
      android:name=".ChronoExampleActivity" 
      android:label="@string/app_name" > 
      <intent-filter> 
       <action android:name="android.intent.action.MAIN" /> 

       <category android:name="android.intent.category.LAUNCHER" /> 
      </intent-filter> 
     </activity> 
     <activity android:name="OtherActivity"></activity> 
    </application> 

</manifest>