本例展示一个Activity怎么接受通过它打开的另外一个Activity返回的结果。
比较常见的例子是，发送短信的时候，需要打开联系人程序选择联系人，然后返回选择的信息到发送程序。
setResult()方法负责发送信息，onActivityResult()方法负责接受信息。
// Definition of the one requestCode we use for receiving resuls.
static final private int GET_CODE = 0;
private OnClickListener mGetListener = new OnClickListener() {
public void onClick(View v) {
// Start the activity whose result we want to retrieve. The
// result will come back with request code GET_CODE.
Intent intent = new Intent(ReceiveResult.this, SendResult.class);
startActivityForResult(intent, GET_CODE);
}
};
startActivityForResult方法启动我们想从那里取得信息的Activity，GET_CODE会在返回信息的时候一起返回，那样我们就通过GET_CODE出来返回的结果。
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www.atcpu.com在SendResult.
java中：
private OnClickListener mCorkyListener = new OnClickListener()
{
public void onClick(View v)
{
// To send a result, simply call setResult() before your
// activity is finished.
setResult(RESULT_OK, (new Intent()).setAction("Corky!"));
finish();
}
};
private OnClickListener mVioletListener = new OnClickListener()
{
public void onClick(View v)
{
// To send a result, simply call setResult() before your
// activity is finished.
setResult(RESULT_OK, (new Intent()).setAction("Violet!"));
finish();
}
};
在程序停止前调用setResult方法返回结果。
@Override
protected void onActivityResult(int requestCode, int resultCode,
Intent data) {
// You can use the requestCode to select between multiple child
// activities you may have started. Here there is only one thing
// we launch.
if (requestCode == GET_CODE) {
// We will be adding to our text.
Editable text = (Editable)mResults.getText();
// This is a standard resultCode that is sent back if the
// activity doesn't supply an explicit result. It will also
// be returned if the activity failed to launch.
if (resultCode == RESULT_CANCELED) {
text.append("(cancelled)");
// Our protocol with the sending activity is that it will send
// text in 'data' as its result.
} else {
text.append("(okay ");
text.append(Integer.toString(resultCode));
text.append(") ");
if (data != null) {
text.append(data.getAction());
}
}
text.append("\n");
}
}
onActivityResult方法接受返回的结果，在onResume方法前执行。三个参数的意思分别是：
1. requestCode就是startActivityForResult中的第二个参数，可以用来区分是哪一个activity发送的请求。
2. resultCode是子activity返回的code，一般为RESULT_OK和RESULT_CANCELLED。
3. data是返回的结果数据。
