Android Activity与Intent详解及示例代码

<?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"> 
  <Button android:layout_width="wrap_content" 
    android:layout_height="wrap_content" android:id="@+id/main1.Button01" 
    android:text="跳转到Activity2"></Button> 
  <EditText android:text="@+id/EditText01" android:id="@+id/EditText01" 
    android:layout_width="wrap_content" android:layout_height="wrap_content"></EditText> 
  <Button android:layout_width="wrap_content" 
    android:layout_height="wrap_content" android:id="@+id/main1.Button02" 
    android:text="跳转到外部Activity"></Button> 
</LinearLayout> 

<?xml version="1.0" encoding="UTF-8"?> 
<LinearLayout android:id="@+id/LinearLayout01" 
  android:layout_width="fill_parent" android:layout_height="fill_parent" 
  xmlns:android="http://schemas.android.com/apk/res/android"> 
  <Button android:layout_width="wrap_content" 
    android:layout_height="wrap_content" android:id="@+id/main2.Button01" 
    android:text="返回Activity1"></Button> 
</LinearLayout> 

package com.testActivityIntent;  
import android.app.Activity;  
import android.content.Intent;  
import android.content.SharedPreferences;  
import android.net.Uri;  
import android.os.Bundle;  
import android.util.Log;  
import android.view.View;  
import android.widget.Button;  
import android.widget.EditText;  
public class testActivityIntent extends Activity {  
  /** Called when the activity is first created. */ 
  Button btnToInternalActivity;  
  Button btnToExternalActivity;  
  EditText tbBundle;  
  @Override 
  public void onCreate(Bundle savedInstanceState) {  
    super.onCreate(savedInstanceState);  
    Log.e("Activity1", "onCreate");//显示当前状态，onCreate与onDestroy对应  
    setContentView(R.layout.main1);  
      
    btnToInternalActivity=(Button)this.findViewById(R.id.main1_Button01);  
    btnToExternalActivity=(Button)this.findViewById(R.id.main1_Button02);  
    btnToInternalActivity.setOnClickListener(new ClickEvent());  
    btnToExternalActivity.setOnClickListener(new ClickEvent());  
    tbBundle=(EditText)this.findViewById(R.id.EditText01);      
  }  
  public void onDestroy()  
  {  
    super.onDestroy();  
    Log.e("Activity1", "onDestroy");//显示当前状态，onCreate与onDestroy对应  
  }  
  @Override 
  public void onStart()  
  {  
    super.onStart();  
    Log.e("Activity1", "onStart");//显示当前状态，onStart与onStop对应  
  }  
  @Override 
  public void onStop()  
  {  
    super.onStop();  
    Log.e("Activity1", "onStop");//显示当前状态，onStart与onStop对应   
  }  
  @Override 
  public void onRestart()  
  {  
    super.onRestart();  
    Log.e("Activity1", "onRestart");  
  }  
  @Override 
  public void onResume()  
  {  
    super.onResume();  
    Log.e("Activity1", "onResume");//显示当前状态，onPause与onResume对应   
    SharedPreferences prefs = getPreferences(0); //SharedPreferences 用于存储数据  
    String restoredText = prefs.getString("editText01", null);  
    if (restoredText != null) {  
      this.tbBundle.setText(restoredText);  
    }  
  }  
  @Override 
  public void onPause()  
  {  
    super.onResume();  
    Log.e("Activity1", "onPause");//显示当前状态，onPause与onResume对应   
    //保存文本框的内容，使得重回本Acitivity的时候可以恢复  
    SharedPreferences.Editor editor = getPreferences(0).edit();//SharedPreferences 用于存储数据  
    editor.putString("editText01", this.tbBundle.getText().toString());  
    editor.commit();  
  }  
    
  class ClickEvent implements View.OnClickListener{  
    @Override 
    public void onClick(View v) {  
      if(v==btnToInternalActivity)  
      {  
        Intent intent = new Intent();  
        intent.setClass(testActivityIntent.this,Activity2.class);  
          
        //new一个Bundle对象，并将要传递的数据传入  
        Bundle bundle = new Bundle();  
        bundle.putString("Text",tbBundle.getText().toString());  
         
        //将Bundle对象assign给Intent  
        intent.putExtras(bundle);  
         
        //调用Activity2  
        startActivity(intent);  
          
        testActivityIntent.this.finish();//会触发onDestroy();  
      }  
      else if(v==btnToExternalActivity)  
      {  
        //有些外部调用需要开启权限  
        Uri uri = Uri.parse("http://google.com");   
        Intent it = new Intent(Intent.ACTION_VIEW, uri);   
        startActivity(it);  
      }  
        
    }  
      
  }  
    
} 

package com.testActivityIntent;  
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 Activity2 extends Activity {  
  Button btnBackMain1;  
  public void onCreate(Bundle savedInstanceState)  
   {  
    super.onCreate(savedInstanceState);  
    Log.e("Activity2", "onCreate");//显示当前状态，onCreate与onDestroy对应  
      
    //加载activity2.xml  
    setContentView(R.layout.main2);  
      
    //得Intent中的Bundle对象  
    Bundle bunde = this.getIntent().getExtras();  
    //取得Bundle对象中的数据  
    Log.i("In_Text", bunde.getString("Text"));  
    btnBackMain1=(Button)this.findViewById(R.id.main2_Button01);  
    btnBackMain1.setOnClickListener(new ClickEvent());  
   }  
    
  public void onDestroy()  
  {  
    super.onDestroy();  
    Log.e("Activity2", "onDestroy");//显示当前状态，onCreate与onDestroy对应  
  }  
  @Override 
  public void onStart()  
  {  
    super.onStart();  
    Log.e("Activity2", "onStart");//显示当前状态，onStart与onStop对应  
  }  
  @Override 
  public void onStop()  
  {  
    super.onStop();  
    Log.e("Activity2", "onStop");//显示当前状态，onStart与onStop对应   
  }  
  @Override 
  public void onRestart()  
  {  
    super.onRestart();  
    Log.e("Activity2", "onRestart");    
  }  
  @Override 
  public void onResume()  
  {  
    super.onResume();  
    Log.e("Activity2", "onResume");//显示当前状态，onPause与onResume对应     
  }  
  @Override 
  public void onPause()  
  {  
    super.onResume();  
    Log.e("Activity2", "onPause");//显示当前状态，onPause与onResume对应   
  }  
    
  class ClickEvent implements View.OnClickListener{  
    @Override 
    public void onClick(View v) {  
      if(v==btnBackMain1)  
      {  
          
        Intent intent = new Intent();  
        intent.setClass(Activity2.this,testActivityIntent.class);  
          
        //调用Activity1  
        startActivity(intent);  
          
        Activity2.this.finish();//会触发onDestroy();  
      }  
        
    }  
      
  }  
}