我有两门课。第一个是活动,第二个是片段,其中有一些EditText。在活动中,我有一个带有async-task的子类,在方法doInBackground中,我得到了一些结果,我保存到变量中。我怎么能把这个变量从子类“我的活动”到这个片段?
当前回答
芬兰湾的科特林版:
在活动:
val bundle = Bundle()
bundle.putBoolean("YourKey1", true)
bundle.putString("YourKey2", "YourString")
val fragment = YourFragment()
fragment.arguments = bundle
val fragmentTransaction = parentFragmentManager.beginTransaction()
fragmentTransaction.replace(R.id.your_container, fragment, fragment.toString())
fragmentTransaction.commit()
在onCreate()片段中:
var value1 = arguments?.getBoolean("YourKey1", default true/false)
var value2 = arguments?.getString("YourKey2", "Default String")
其他回答
使用Fragments (F)的基本想法是在android应用程序中创建可重用的自我维持UI组件。这些片段包含在活动中,有常见的(最好的)方法来创建从A -> F和F-A的通信路径,这是必须通过一个活动在F-F之间进行通信,因为这样只有片段变得解耦和自我维持。
因此,从A -> F传递数据将是相同的ρ σ η η K.除了这个答案,在一个活动内创建Fragments之后,我们还可以将数据传递给Fragments调用Fragments中的方法。
例如:
ArticleFragment articleFrag = (ArticleFragment)
getSupportFragmentManager().findFragmentById(R.id.article_fragment);
articleFrag.updateArticleView(position);
Very old post, still I dare to add a little explanation that would had been helpful for me. Technically you can directly set members of any type in a fragment from activity. So why Bundle? The reason is very simple - Bundle provides uniform way to handle:-- creating/opening fragment -- reconfiguration (screen rotation) - just add initial/updated bundle to outState in onSaveInstanceState() -- app restoration after being garbage collected in background (as with reconfiguration). You can (if you like experiments) create a workaround in simple situations but Bundle-approach just doesn't see difference between one fragment and one thousand on a backstack - it stays simple and straightforward. That's why the answer by @Elenasys is the most elegant and universal solution. And that's why the answer given by @Martin has pitfalls
有时你可以在你的活动中接收Intent,你需要将信息传递给你的工作片段。 给出的答案是OK,如果你需要启动片段,但如果它仍在工作,setArguments()不是很有用。 如果传递的信息将导致与UI交互,则会出现另一个问题。在这种情况下,你不能调用像myfragment.passData()这样的东西,因为android会迅速告诉只有创建视图的线程可以与之交互。
所以我的建议是使用接收器。这样,您可以从任何地方发送数据,包括活动,但是工作将在片段的上下文中完成。
在你的片段的onCreate():
protected DataReceiver dataReceiver;
public static final String REC_DATA = "REC_DATA";
@Override
public void onCreate(Bundle savedInstanceState) {
data Receiver = new DataReceiver();
intentFilter = new IntentFilter(REC_DATA);
getActivity().registerReceiver(dataReceiver, intentFilter);
}
private class DataReceiver extends BroadcastReceiver {
@Override
public void onReceive(Context context, Intent intent) {
int data= intent.getIntExtra("data", -1);
// Do anything including interact with your UI
}
}
在你的活动:
// somewhere
Intent retIntent = new Intent(RE_DATA);
retIntent.putExtra("data", myData);
sendBroadcast(retIntent);
你也可以从片段访问活动数据:
活动:
public class MyActivity extends Activity {
private String myString = "hello";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_my);
...
}
public String getMyData() {
return myString;
}
}
片段:
public class MyFragment extends Fragment {
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
MyActivity activity = (MyActivity) getActivity();
String myDataFromActivity = activity.getMyData();
return view;
}
}
在你的活动中声明静态变量
public static HashMap<String,ContactsModal> contactItems=new HashMap<String, ContactsModal>();
然后在你的片段中像这样做
ActivityName.contactItems.put(Number,contactsModal);
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