Android應用程式的生命週期(Life Cycle)

這是一個認識Android應用程式生命週期的練習.



通過這個練習知道, 原來按下HOME按鈕離開應用程式, 和按下BACK按鈕或調用finish()方法離開應用程式是不相同的.

按下HOME按鈕離開應用程式, 會順序調用: OnPause() -> OnStop().
再次進入應用程式會調用: OnReStart() -> OnStart() -> OnResume().

按下BACK按鈕或調用finish()方法離開應用程式: OnPause() -> OnStop() -> onDestroy().
再次進入應用程式會調用: OnCreate() -> OnStart() -> OnResume().

main.xml

<?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"
   >
<TextView 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="@string/hello"
   />
<Button
   android:id="@+id/finish" 
   android:layout_width="fill_parent"
   android:layout_height="wrap_content"
   android:text="exit App by finish()"
   />
</LinearLayout>

主要Java代碼

package com.AndroidLifeCycle;

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

public class AndroidLifeCycle extends Activity {
   /** Called when the activity is first created. */
   @Override
   public void onCreate(Bundle savedInstanceState) {
       super.onCreate(savedInstanceState);
       setContentView(R.layout.main);
      
       Button finish = (Button)findViewById(R.id.finish);
       finish.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    finish();
   }});
      
       Toast.makeText(this, "onCreate", Toast.LENGTH_LONG).show();
      
   }

 @Override
 protected void onDestroy() {
  // TODO Auto-generated method stub
  super.onDestroy();
  Toast.makeText(this, "onDestroy", Toast.LENGTH_LONG).show();
 }

 @Override
 protected void onPause() {
  // TODO Auto-generated method stub
  super.onPause();
  Toast.makeText(this, "onPause", Toast.LENGTH_LONG).show();
 }

 @Override
 protected void onRestart() {
  // TODO Auto-generated method stub
  super.onRestart();
  Toast.makeText(this, "onRestart", Toast.LENGTH_LONG).show();
 }

 @Override
 protected void onResume() {
  // TODO Auto-generated method stub
  super.onResume();
  Toast.makeText(this, "onResume", Toast.LENGTH_LONG).show();
 }

 @Override
 protected void onStart() {
  // TODO Auto-generated method stub
  super.onStart();
  Toast.makeText(this, "onStart", Toast.LENGTH_LONG).show();
 }

 @Override
 protected void onStop() {
  // TODO Auto-generated method stub
  super.onStop();
  Toast.makeText(this, "onStop", Toast.LENGTH_LONG).show();
 }
}