Android(安卓)API Demos学习(4) - Receive Result - android

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。
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。

@Overrideprotected 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。

Android(安卓)API Demos学习(4) - Receive Result

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