android_activity_研究(二)

这次开始玩玩活动的生命周期。废话不说，先搞个小应用，大体思路是：主界面有两个按钮，一个按钮按下后，出现第二个界面；另一个按钮按下后，出现第三个界面，真他妈简单。

一、主界面：

1. 主界面布局xml文件：

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="@string/hello" />

    <Button
        android:id="@+id/btnToSecond"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="callSecondActivity" />

    <Button
        android:id="@+id/btnToThird"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="callThirdActivity" />

</LinearLayout>

我的神~~~

2. 主界面逻辑代码：

package cn.com.sxp;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;

public class ActivityLifeActivity extends Activity {
    private static final String TAG = ActivityLifeActivity.class
            .getSimpleName();
    private Button btnToSecond = null;
    private Button btnToThird = null;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);

        Log.i(TAG, "ActivityLifeActivity onCreate()");

        btnToSecond = (Button) this.findViewById(R.id.btnToSecond);
        btnToSecond.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(ActivityLifeActivity.this,
                        secondActivity.class);
                startActivity(intent);
            }
        });

        btnToThird = (Button) this.findViewById(R.id.btnToThird);
        btnToThird.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View v) {
                Intent intent = new Intent(ActivityLifeActivity.this,
                        thirdActivity.class);
                startActivity(intent);
            }
        });
    }
    
    @Override 
    protected void onDestroy() { 
        Log.i(TAG, "ActivityLifeActivity onDestroy()"); 
        super.onDestroy(); 
    } 
 
    @Override 
    protected void onPause() { 
         Log.i(TAG, "ActivityLifeActivity onPause()"); 
        super.onPause(); 
    } 
 
    @Override 
    protected void onRestart() { 
         Log.i(TAG, "ActivityLifeActivity onRestart()"); 
        super.onRestart(); 
    } 
 
    @Override 
    protected void onResume() { 
         Log.i(TAG, "ActivityLifeActivity onResume()"); 
        super.onResume(); 
    } 
 
    @Override 
    protected void onStart() { 
         Log.i(TAG, "ActivityLifeActivity onStart()"); 
        super.onStart(); 
    } 
 
    @Override 
    protected void onStop() { 
         Log.i(TAG, "ActivityLifeActivity onStop()"); 
        super.onStop(); 
    } 
}

漂亮：这样的话，搞出来的界面就是：

跑出来的日志：

可以看到，主界面活动经过了创建、开始、恢复三个状态。

二、第二个界面

1. 界面的xml文件

<?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="欢迎来到第二个活动" 
    /> 
</LinearLayout>

很简单，就一个文本框，说着一些废话。

2. 第二个见面的逻辑代码：

package cn.com.sxp;

import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import cn.com.sxp.R;

public class secondActivity extends Activity {
    private static final String TAG = secondActivity.class.getSimpleName();
    @Override 
    protected void onCreate(Bundle savedInstanceState) { 
        // TODO Auto-generated method stub 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.second); 
        
        Log.i(TAG, "secondActivity onCreate()");
    }
    
    @Override 
    protected void onDestroy() { 
        Log.i(TAG, "secondActivity onDestroy()"); 
        super.onDestroy(); 
    } 
 
    @Override 
    protected void onPause() { 
         Log.i(TAG, "secondActivity onPause()"); 
        super.onPause(); 
    } 
 
    @Override 
    protected void onRestart() { 
         Log.i(TAG, "secondActivity onRestart()"); 
        super.onRestart(); 
    } 
 
    @Override 
    protected void onResume() { 
         Log.i(TAG, "secondActivity onResume()"); 
        super.onResume(); 
    } 
 
    @Override 
    protected void onStart() { 
         Log.i(TAG, "secondActivity onStart()"); 
        super.onStart(); 
    } 
 
    @Override 
    protected void onStop() { 
         Log.i(TAG, "secondActivity onStop()"); 
        super.onStop(); 
    }
}