Android API Demos学习(4) - Receive Result

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。

www.zzzyk.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。

补充：移动开发 , Android ,