Android新手入門教程（十）：使用Intents連結Activitiesの返回結果

startActivity()方法可以調用另外的Activity，但這種方法不會給當前的Activity返回一個結果。例如，你有一個Activity提示使用者輸入使用者名稱和密碼，使用者輸入的資訊需要被“回傳”給這個輸入資訊的Activity，那就需要使用startActivityForResult()方法。

    1.secondactivity.xml中的代碼。

[java] <?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="This is the Second Activity!" /> 
 
    <TextView 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:text="Please enter your name" /> 
 
    <EditText 
        android:id="@+id/txt_username" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" /> 
 
    <Button 
        android:id="@+id/btn_OK" 
        android:layout_width="fill_parent" 
        android:layout_height="wrap_content" 
        android:onClick="onClick" 
        android:text="OK" /> 
 
</LinearLayout> 
<?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="This is the Second Activity!" />

    <TextView
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="Please enter your name" />

    <EditText
        android:id="@+id/txt_username"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content" />

    <Button
        android:id="@+id/btn_OK"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:onClick="onClick"
        android:text="OK" />

</LinearLayout>    2.SecondActivity.java中的代碼。

[java] package net.horsttnann.UsingIntent; 
 
import android.app.Activity; 
import android.content.Intent; 
import android.net.Uri; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.EditText; 
 
public class SecondActivity extends Activity { 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.secondactivity); 
    } 
 
    public void onClick(View view) { 
        Intent data = new Intent(); 
 
        // ---get the EditText view---  
        EditText txt_username = (EditText) findViewById(R.id.txt_username); 
 
        // ---set the data to pass back---  
        data.setData(Uri.parse(txt_username.getText().toString())); 
        setResult(RESULT_OK, data); 
 
        // ---closes the activity---  
        finish(); 
    } 
} 
package net.horsttnann.UsingIntent;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;

public class SecondActivity extends Activity {
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.secondactivity);
    }

    public void onClick(View view) {
        Intent data = new Intent();

        // ---get the EditText view---
        EditText txt_username = (EditText) findViewById(R.id.txt_username);

        // ---set the data to pass back---
        data.setData(Uri.parse(txt_username.getText().toString()));
        setResult(RESULT_OK, data);

        // ---closes the activity---
        finish();
    }
}
    3.UsingIntentActivity.java中的代碼。

[java] package net.horsttnann.UsingIntent; 
 
 
import android.app.Activity; 
import android.content.Intent; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.Toast; 
 
 
public class UsingIntentActivity extends Activity { 
    int request_Code = 1; 
 
 
    /** Called when the activity is first created. */ 
    @Override 
    public void onCreate(Bundle savedInstanceState) { 
        super.onCreate(savedInstanceState); 
        setContentView(R.layout.main); 
    } 
 
 
    public void onClick(View view) { 
        // startActivity(new Intent("net.horsttnann.SecondActivity"));  
        // or  
        // startActivity(new Intent(this, SecondActivity.class));  
 
 
        startActivityForResult(new Intent("net.horsttnann.SecondActivity"), 
                request_Code); 
    } 
 
 
    public void onActivityResult(int requestCode, int resultCode, Intent data) { 
        if (requestCode == request_Code) { 
            if (resultCode == RESULT_OK) { 
                Toast.makeText(this, data.getData().toString(), 
                        Toast.LENGTH_SHORT).show(); 
            } 
        } 
    } 
} 
package net.horsttnann.UsingIntent;

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

public class UsingIntentActivity extends Activity {
    int request_Code = 1;

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

    public void onClick(View view) {
        // startActivity(new Intent("net.horsttnann.SecondActivity"));
        // or
        // startActivity(new Intent(this, SecondActivity.class));

        startActivityForResult(new Intent("net.horsttnann.SecondActivity"),
                request_Code);
    }

    public void onActivityResult(int requestCode, int resultCode, Intent data) {
        if (requestCode == request_Code) {
            if (resultCode == RESULT_OK) {
                Toast.makeText(this, data.getData().toString(),
                        Toast.LENGTH_SHORT).show();
            }
        }
    }
}    4.按F11調試。

 

：

    程式第一次被載入：

 
    點擊按鈕，使用startActivityForResult()方法調用SecondActivity：

    點擊OK按鈕，返回到UsingIntentActivity：

  

摘自  horsttnann的專欄