从内部重新加载片段

Question

我一直试图弄清楚如何从Fragment中定义的菜单按钮刷新我的Fragment.

我在这里看过这个问题,但我希望有一个更详细的例子来说明我将如何实现这个目标.

任何帮助或指导将不胜感激,谢谢.

@Override
public boolean onOptionsItemSelected(MenuItem item) {
    switch (item.getItemId()) {
    case R.id.clear_cache:
        mImageFetcher.clearCache();
        Toast.makeText(getActivity(), R.string.clear_cache_complete_toast,
                Toast.LENGTH_SHORT).show();
        break;

    case R.id.random:

        //Reload the fragment from here

        getActivity().getSupportFragmentManager().beginTransaction()
        .replace(R.id.gridView, new Fragment3())
        .commit();


        return true;
    }
    return super.onOptionsItemSelected(item);

XML:

        <activity
        android:name="com.stackoverflow.question.ImageGridActivity"
        android:label="@string/app_name"
        android:screenOrientation="portrait"
        android:theme="@style/AppTheme" >
        </activity>

崩溃:

12-04 09:48:27.636: E/AndroidRuntime(20461): FATAL EXCEPTION: main
12-04 09:48:27.636: E/AndroidRuntime(20461): java.lang.UnsupportedOperationException: addView(View) is not supported in AdapterView
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.widget.AdapterView.addView(AdapterView.java:451)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:938)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1104)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:682)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.os.Handler.handleCallback(Handler.java:615)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.os.Handler.dispatchMessage(Handler.java:92)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.os.Looper.loop(Looper.java:213)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at android.app.ActivityThread.main(ActivityThread.java:4787)
 12-04 09:48:27.636: E/AndroidRuntime(20461):   at java.lang.reflect.Method.invokeNative(Native Method)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at java.lang.reflect.Method.invoke(Method.java:511)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
12-04 09:48:27.636: E/AndroidRuntime(20461):    at dalvik.system.NativeStart.main(Native Method)

当使用@Matthew Mcveigh回答时:

12-04 10:05:09.315: E/AndroidRuntime(21072): FATAL EXCEPTION: main
12-04 10:05:09.315: E/AndroidRuntime(21072): java.lang.NullPointerException
12-04 10:05:09.315: E/AndroidRuntime(21072):    at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:666)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1467)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at android.support.v4.app.FragmentManagerImpl$1.run(FragmentManager.java:440)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at android.os.Handler.handleCallback(Handler.java:615)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at android.os.Handler.dispatchMessage(Handler.java:92)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at android.os.Looper.loop(Looper.java:213)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at android.app.ActivityThread.main(ActivityThread.java:4787)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at java.lang.reflect.Method.invokeNative(Native Method)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at java.lang.reflect.Method.invoke(Method.java:511)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:809)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:576)
12-04 10:05:09.315: E/AndroidRuntime(21072):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

里面片段放这些:

private Callbacks mCallbacks;


public interface Callbacks {
        //Callback for when button clicked.
        public void onButtonClicked();
}


@Override
public void onAttach(Activity activity) {
        super.onAttach(activity);
        // Activities containing this fragment must implement its callbacks
        mCallbacks = (Callbacks) activity;

}

在onOptionsItemSelected中更改为

case R.id.random:

mCallbacks.onButtonClicked();
break;

使FragmentActivity实现YourFragment.Callbacks:

public class YourActivityName extends FragmentActivity implements YourFragment.Callbacks

在包含Fragment的FragmentActivity里面添加:

    @Override
    public void onButtonClicked() {
        getSupportFragmentManager().beginTransaction()
        .replace(R.id.gridView, new Fragment3())
        .commit();

    }

Answer 2

这可以用 2 行来完成，只需将它们添加到刷新/重新加载按钮中（Kotlin 代码）

try_again_button.setOnClickListener {
                val ft = fragmentManager!!.beginTransaction()
                ft.detach(this).attach(this).commit()
            }