两个Activity之间的交互startActivityForResult的使用

代码如下：

 package com.zzw.teststartintentforrequest;

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

 public class MainActivity extends Activity {

     private final int REQUESTCODE_MAIN = 1;

     private final String KEY_MAIN = "key_main";
     private final String KEY_B = "key_b";

     private TextView textView;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activity_main);

         textView = (TextView) findViewById(R.id.textView_main);

         findViewById(R.id.button_main).setOnClickListener(new OnClickListener() {

             @Override
             public void onClick(View v) {
                 Intent intent = new Intent(MainActivity.this, ActivityB.class);
                 int a=(int) (Math.random()*100);
                 int b=(int) (Math.random()*100);
                 int[] nums = { a, b };
                 intent.putExtra(KEY_MAIN, nums);
                 startActivityForResult(intent, REQUESTCODE_MAIN);
             }
         });
     }

     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
         if(data!=null){
             Log.d("-------", "requestCode:"+requestCode+"   resultCode:"+resultCode);
             textView.setText(data.getIntExtra(KEY_B, 0)+"");
         }
     }
 }

MainActivity.java

 package com.zzw.teststartintentforrequest;

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

 public class ActivityB extends Activity {

     private final int RESULTCODE_B=2;

     private final String KEY_MAIN="key_main";
     private final String KEY_B="key_b";

     private TextView textView;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
         super.onCreate(savedInstanceState);
         setContentView(R.layout.activityb);

         textView=(TextView) findViewById(R.id.textView_B);

         int nums[]=this.getIntent().getIntArrayExtra(KEY_MAIN);

         final int sum=nums[0]+nums[1];

         textView.setText(nums[0]+"+"+nums[1]+"="+sum);

         findViewById(R.id.button_B).setOnClickListener(new OnClickListener() {

             @Override
             public void onClick(View v) {
                 Intent intent=new Intent(ActivityB.this,MainActivity.class);
                 intent.putExtra(KEY_B,sum);
                 ActivityB.this.setResult(RESULTCODE_B, intent);
                 ActivityB.this.finish();
             }
         });
     }

 }

ActivityB.java

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@android:color/holo_blue_light"
     tools:context="com.zzw.teststartintentforrequest.MainActivity" >

     <TextView
         android:id="@+id/textView_main"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_centerInParent="true"
         android:text="0"
         android:textColor="@android:color/holo_red_light"
         android:textSize="30sp" />

     <Button
         android:id="@+id/button_main"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_alignParentBottom="true"
         android:layout_centerHorizontal="true"
         android:layout_marginBottom="38dp"
         android:background="@android:color/holo_blue_light"
         android:text="点击跳转AcyivityB"
         android:textColor="@android:color/holo_red_light" />

 </RelativeLayout>

activity_main.xml

 <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
     xmlns:tools="http://schemas.android.com/tools"
     android:layout_width="match_parent"
     android:layout_height="match_parent"
     android:background="@android:color/black"
     tools:context="com.zzw.teststartintentforrequest.MainActivity" >

     <TextView
         android:id="@+id/textView_B"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:layout_centerInParent="true"
         android:textColor="@android:color/white"
         android:textSize="30sp" />

     <Button
         android:id="@+id/button_B"
         android:layout_width="wrap_content"
         android:layout_height="wrap_content"
         android:textColor="@android:color/white"
         android:background="@android:color/black"
         android:layout_alignParentBottom="true"
         android:layout_centerHorizontal="true"
         android:layout_marginBottom="38dp"
         android:text="点击返回MainAcyivity" />

 </RelativeLayout>

activityb.xml