[英]Switching fragments in navigation drawer
我希望能够使用导航抽屉并根据导航中的选择在不同的片段之间进行更改。
我正在使用Android Studio,基本上我所做的是:
然后,我在onNavigationDrawerItemSelected方法中更改了一些代码。
@Override
public void onNavigationDrawerItemSelected(int position) {
// update the main content by replacing fragments
FragmentManager fragmentManager = getSupportFragmentManager();
Fragment fragment = new BlankFragment();
fragmentManager.beginTransaction()
.replace(R.id.container, fragment)
.commit();
}
我的程序崩溃了,并给了我很多我不理解的错误。 我究竟做错了什么?
4168-4168/com.dev.kim.mytestapplication E/AndroidRuntime﹕ FATAL
EXCEPTION: main
Process: com.dev.kim.mytestapplication, PID: 4168
java.lang.RuntimeException: Unable to start activity ComponentInfo{com.dev.kim.mytestapplication/com.dev.kim.mytestapplication.MainActivity}:
java.lang.ClassCastException:
com.dev.kim.mytestapplication.MainActivity@e71881c must implement
OnFragmentInteractionListener
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2298)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
Caused by: java.lang.ClassCastException: com.dev.kim.mytestapplication.MainActivity@e71881c must implement
OnFragmentInteractionListener
at com.dev.kim.mytestapplication.BlankFragment.onAttach(BlankFragment.java:83)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:903)
at android.support.v4.app.FragmentManagerImpl.moveToState(FragmentManager.java:1126)
at android.support.v4.app.BackStackRecord.run(BackStackRecord.java:739)
at android.support.v4.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1489)
at android.support.v4.app.FragmentActivity.onStart(FragmentActivity.java:548)
at android.app.Instrumentation.callActivityOnStart(Instrumentation.java:1220)
at android.app.Activity.performStart(Activity.java:5949)
at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2261)
at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2360)
at android.app.ActivityThread.access$800(ActivityThread.java:144)
at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1278)
at android.os.Handler.dispatchMessage(Handler.java:102)
at android.os.Looper.loop(Looper.java:135)
at android.app.ActivityThread.main(ActivityThread.java:5221)
at java.lang.reflect.Method.invoke(Native Method)
at java.lang.reflect.Method.invoke(Method.java:372)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:899)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:694)
使用向导创建“ Fragment
时,您留下了一个复选框以创建一个侦听器。
所以你得到这个错误:
must implement
OnFragmentInteractionListener
如果您不想使用侦听器,则可以在“ onAttach”中删除以下代码块:
try {
mListener = (OnFragmentInteractionListener) activity;
} catch (ClassCastException e) {
throw new ClassCastException(activity.toString()
+ " must implement OnFragmentInteractionListener");
}
或者,您可以在活动中实现侦听器。
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