startActivityForResult 和 onActivityResult

上兩篇文章"活動(activity)和意圖(intent)"和"包裹(Bundle)"使用startActivity(Intent)啟動另一項新活動, 原本的活動不會收到任何有關新活動退出時的信息. 這篇文章使用startActivityForResult(Intent, int)啟動新活動, 並重寫onActivityResult(int, int, Intent)方法. 當該新活動退出時, 會回調onActivityResult(int, int, Intent)方法.



修改主佈局(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"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Your Name?"
  />
<EditText
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:id="@+id/inamefield"
  />
<Button
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="Launch Activity2"
  android:id="@+id/launchbutton"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:id = "@+id/phonenumber"
  android:text=""
  />
</LinearLayout>

修改主活動代碼:

package com.AndroidIntent;

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;

public class AndroidIntent extends Activity {
 
 int REQUEST_CODE = 0;
 TextView phoneNumber;
 
  /** Called when the activity is first created. */
  @Override
  public void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.main);
      Button launchButton = (Button)findViewById(R.id.launchbutton);
      final EditText iNameField = (EditText)findViewById(R.id.inamefield);
      phoneNumber = (TextView)findViewById(R.id.phonenumber);
      launchButton.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View arg0) {
    // TODO Auto-generated method stub
    Intent newIntent = new Intent(AndroidIntent.this, Activity2.class);
    newIntent.putExtra("name", iNameField.getText().toString());
    
    startActivityForResult(newIntent, REQUEST_CODE);
   }});
  }

 @Override
 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
  // TODO Auto-generated method stub
  super.onActivityResult(requestCode, resultCode, data);
  
  if(requestCode == REQUEST_CODE){
   if(resultCode==RESULT_OK){
    Bundle extras = data.getExtras();
    if (extras != null){
     phoneNumber.setText("Phone #: " + extras.getString("phonenumber"));
    }
   }
  }
 }
}

修改layout2.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="It's Activity2"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:id="@+id/onamefield"
  />
<TextView
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="what's your phone number?"
  />
<EditText
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:id="@+id/phonenumberfield"
  />
<Button
  android:layout_width="fill_parent"
  android:layout_height="wrap_content"
  android:text="OK"
  android:id="@+id/okbutton"
  />
</LinearLayout>

修改Activity2代碼:

package com.AndroidIntent;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;


public class Activity2 extends Activity {

 @Override
 protected void onCreate(Bundle savedInstanceState) {
  // TODO Auto-generated method stub
  super.onCreate(savedInstanceState);
  setContentView(R.layout.layout2);
  TextView oNameField = (TextView)findViewById(R.id.onamefield);
  final EditText phoneNumber = (EditText)findViewById(R.id.phonenumberfield);
  Button okButton = (Button)findViewById(R.id.okbutton);
  
  Bundle extras = getIntent().getExtras();
  oNameField.setText("Hello " + extras.getString("name"));
  
  okButton.setOnClickListener(new Button.OnClickListener(){

   @Override
   public void onClick(View v) {
    // TODO Auto-generated method stub
    Bundle bundle = new Bundle();
    bundle.putString("phonenumber", phoneNumber.getText().toString());
    Intent intent = new Intent();
    intent.putExtras(bundle);
    setResult(RESULT_OK, intent);
    finish();
   }});
 }
}

記住, 需要修改清單文件(AndroidManifest.xml)加入ctivity2, 參考"活動(activity)和意圖(intent)".