该Demo演示了如何使用startActivityForResult从被启动的Activity中得到一个返回结果,主要学到的如下:
- startActivityForResult的使用
- Request Code与Result Code的作用
演示如下:
![](http://img-my.csdn.net/uploads/201211/19/1353255473_9308.png)
2.视频讲解
http://www.eyeandroid.com/thread-10471-1-1.html
3.Demo分析
startActivity可以启动一个新的Activity,这个新的Activity与启动它Activity之间相对独立,不会返回给调用它的Activity如何结果。在写应用时,有时需要从其它Activity返回结果。Receive Result显示了这个用法。
startActivityForResult 使用方法和startActivity类似,重要的是startActivityForResult可以从被调用的Activity返回结果。GET_CODE为Request code,当子Activity返回结果时可以根据这个Request Code来处理Activity返回的结果。
- // 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);
- }
- };
当子Activity结束时,调用setResult 来设置返回结果。Receive Result例子中涉及了两个Activity, ReceiveResult为父Activity,SendResult为子Activity返回用户选项,返回的结果在ReceiveResult中显示。
SendResult 返回结果的代码如下:
- 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();
- }
- };
当从子Activity返回结果后,父Activity通过定义onActivityResult来处理子Activity返回的结果。
- 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.
- ...
- }
- }
onActivityResult中的三个参数:
requestCode: 就是在调用startActivityForResult 时的request code,可以使用request code 来区分多个子Acitivity。
resultCode:为子Activity的返回值,一般为RESULT_OK (正常),RESULT_CANCELLED(取消)。
Data: Activity的返回结果。例子中为用户选择的Corky或是Violet。
4.这个Demo我们学会了
http://www.eyeandroid.com/thread-10257-1-1.html
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