本节演示了父Activity跳转到子Activity后，接收子Activity传递回的数据。需要注意在Manifest.xml中注册子Activity。
基本步骤
1)在父Activity这边，Activity跳转时调用startActivityForResult方法，然后重写onActivityResult（）方法用于接收子Activity传回的数据。
2)在子Activity这边，调用setResult（）函数设置返回值。
具体解释见代码：
父Activity ReceiveResult.java：
1 public class ReceiveResult extends Activity {
2 @Override
3 protected void onCreate(Bundle savedInstanceState) {
4 super.onCreate(savedInstanceState);
5 setContentView(R.layout.receive_result);
6
7 mResults = (TextView)findViewById(R.id.results);
8
9 mResults.setText(mResults.getText(), TextView.BufferType.EDITABLE);
10 Button getButton = (Button)findViewById(R.id.get);
11 getButton.setOnClickListener(mGetListener);
12 }
13
14 @Override
15 protected void onActivityResult(int requestCode, int resultCode, Intent data) {
16 // 如果有多个子Activity都返回数据的话，可以用requestCode来区分是哪个子Activity返回的数据，但本例中只有一个Activity.
17 if (requestCode == GET_CODE) {
18 Editable text = (Editable)mResults.getText();
19
20 // 如果子Activity启动失败或者没有传回参数，则resultCode就为RESULT_CANCELED
21 if (resultCode == RESULT_CANCELED) {
22 text.append("(cancelled)");
23
24 // Our protocol with the sending activity is that it will send
25 // text in 'data' as its result.
26 } else {
27 text.append("(okay ");
28 text.append(Integer.toString(resultCode));
29 text.append(") ");
30 if (data != null) {
31 text.append(data.getAction());
32 }
33 }
34 text.append("\n");
35 }
36 }
37
38 static final private int GET_CODE = 0;
39
40 private OnClickListener mGetListener = new OnClickListener() {
41 public void onClick(View v) {
42 // 若需获取子Activity传递回来的数值，此处就不再是调用startActivity()函数了，而是调用startActivityForResult()函数，
43 // 参数GET_CODE用来区分是哪个子Activity传回的数据。需要重写onActivityResult()函数。
44 Intent intent = new Intent(ReceiveResult.this, SendResult.class);
45 startActivityForResult(intent, GET_CODE);
46 }
47 };
48
49 private TextView mResults;
50 }
子Activity ReceiveResult.java
1 public class SendResult extends Activity
2 {
3 protected void onCreate(Bundle savedInstanceState)
4 {
5 super.onCreate(savedInstanceState);
6
7 setContentView(R.layout.send_result);
8
9 Button button = (Button)findViewById(R.id.corky);
10 button.setOnClickListener(mCorkyListener);
11 button = (Button)findViewById(R.id.violet);
12 button.setOnClickListener(mVioletListener);
13 }
14
15 private OnClickListener mCorkyListener = new OnClickListener()
16 {
17 public void onClick(View v)
18 {
19 // 在Activity finish之前，调用setResult函数，确定本activity返回的值
20
21 setResult(RESULT_OK, (new Intent()).setAction("Corky!"));
22 finish();
23 }
24 };
25
26 private OnClickListener mVioletListener = new OnClickListener()
27 {
28 public void onClick(View v)
29 {
30 // To send a result, simply call setResult() before your
31 // activity is finished.
32 setResult(RESULT_OK, (new Intent()).setAction("Violet!"));
33 finish();
34 }
35 };
36 }
布局文件比较简单，就不放出了，以上即可。