如何从子子活动中获取结果代码？

Question

假设我有3项活动。 活动A启动活动B，活动B启动活动C.

在活动A中我有代码

Intent i = new Intent(A.this, B.class);
startActivityForResult(i, SOME_NUMBER);

在活动B中，我有代码：

Intent i = new Intent(B.this, C.class);
finish(); // this activity should die and start the C activity
startActivityForResult(i, SOME_NUMBER);

最后在活动C中我有代码：

setResult(RESULT_OK);
finish();

我的问题是活动A没有收到活动C放置的resultCode。 我在活动A中的onActivityResult（int，int Intent）方法如下所示：

switch(requestCode){
case SOME_NUMBER:
    if(resultCode == RESULT_OK){
        // the activity C has returned RESULT_OK
    }else if(resultCode == RESULT_CANCELED){
        // the activity C has returned RESULT_CANCELED
    }
break;
}

它始终输入else if（resultCode == RESULT_CANCELED） 我想知道如何将正确的resultCode从C活动传递给A活动。

Answer 1

完成（） - 在您的活动完成后调用此应该关闭。      所以你总是得到Resultcode 0（RESULT_CANCELED = 0）。

示例：

<强> first_layout.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:id="@+id/textView"
     android:layout_width="fill_parent" 
     android:layout_height="70px"/>
</LinearLayout>

<强> FirstActivity.java：

package com.example.startforresultdemo;

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

public class FirstActivity extends Activity {
     TextView textView;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.first_layout);      
        textView = (TextView)this.findViewById(R.id.textView);

        Intent intent = new Intent(this, SecondActivity.class);
        intent.putExtra("sampleData", "This is Sample Data");
        startActivityForResult(intent, 1);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.first, menu);
        return true;
    }

     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      super.onActivityResult(requestCode, resultCode, data);
      if(resultCode==RESULT_OK && requestCode==1){
       String msg = data.getStringExtra("returnedData");
       textView.setText(msg);
      }else{
          Log.i("babu", "requestCode "+requestCode+" resultCode "+resultCode);
          //String msg = data.getStringExtra("returnedData");
           textView.setText("requestCode "+requestCode+" resultCode "+resultCode);
      }
     }

}

<强> SecondActivity.java：

import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;

public class SecondActivity extends Activity{

     Intent intent;

     @Override
     protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      intent= getIntent();
      String msg = intent.getStringExtra("sampleData");
      msg += ", Added at Second";

      Intent intent2 = new Intent(this, ThirdActivity.class);
      intent2 .putExtra("sampleData", msg);   
      startActivityForResult(intent2, 10);
      //finish();
     }

     @Override
     protected void onActivityResult(int requestCode, int resultCode, Intent data) {
      super.onActivityResult(requestCode, resultCode, data);
      if(resultCode==RESULT_OK && requestCode==10){
       String msg = data.getStringExtra("returnedData");
       intent.putExtra("returnedData", msg);
       setResult(RESULT_OK, intent);
       finish();
      }
     }



}

<强> ThirdActivity.java：

package com.example.startforresultdemo;
import android.app.Activity;
import android.content.Intent;
import android.os.Bundle;

public class ThirdActivity extends Activity{    
     @Override
     protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      Intent intent= getIntent();
      String msg = intent.getStringExtra("sampleData");
      msg += ", Added at Third";
      intent.putExtra("returnedData", msg);
      setResult(RESULT_OK, intent);
      finish();
     }

}

或按照您的意愿将以下代码添加到您的课程中。您可以从third activity获得结果。

<强> FirstActivity.java：

  if(getIntent().getStringExtra("returnedData") != null){          
              Intent intent= getIntent();
              String msg = intent.getStringExtra("returnedData");           
              textView.setText(msg);

       }else{
           Intent intent = new Intent(this, SecondActivity.class);
           intent.putExtra("sampleData", "This is Sample Data");          
           startActivity(intent);
       }

       SecondActivity.java:
      intent= getIntent();
      String msg = intent.getStringExtra("sampleData");
      msg += ", Added at Second";     
      Intent intent2 = new Intent(this, ThirdActivity.class);
      intent2 .putExtra("sampleData", msg);     
      finish(); 
      startActivity(intent2);

      ThirdActivity.java
      Intent intent= getIntent();
      String msg = intent.getStringExtra("sampleData");
      msg += ", Added at Third";
      Intent intent1 = new Intent(this, FirstActivity.class);
      intent1.putExtra("returnedData", msg);
      startActivity(intent1);
      finish();