Question

我有以下问题：

当我从fragment1切换到fragment2时，我得到一个nullpointer异常 fragment2有一个带过滤器的searchview。某些移动电话出现错误，我不知道为什么。

应用程序在mListAdapter.getFilter（）中崩溃。在那里过滤：

        @Override
public boolean onQueryTextChange(String newText) {
    mListAdapter.getFilter().filter(newText);
    lv.setAdapter(mListAdapter);

    return false;
}

这是Logcat：

08-25 09:18:25.840: E/AndroidRuntime(1430): FATAL EXCEPTION: main
08-25 09:18:25.840: E/AndroidRuntime(1430): java.lang.NullPointerException
08-25 09:18:25.840: E/AndroidRuntime(1430):     at com.kansosystem.fragments.FragmentList.onQueryTextChange(FragmentList.java:291)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.SearchView.onTextChanged(SearchView.java:1154)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.SearchView.access$2000(SearchView.java:92)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.SearchView$11.onTextChanged(SearchView.java:1623)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.TextView.sendOnTextChanged(TextView.java:7079)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.TextView.setText(TextView.java:3550)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.TextView.setText(TextView.java:3405)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.EditText.setText(EditText.java:80)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.TextView.setText(TextView.java:3380)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.widget.TextView.onRestoreInstanceState(TextView.java:3280)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.view.View.dispatchRestoreInstanceState(View.java:11910)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2590)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2590)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2590)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.view.ViewGroup.dispatchRestoreInstanceState(ViewGroup.java:2590)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.view.View.restoreHierarchyState(View.java:11888)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at com.android.internal.view.menu.MenuBuilder.restoreActionViewStates(MenuBuilder.java:358)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at com.android.internal.policy.impl.PhoneWindow.preparePanel(PhoneWindow.java:417)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at com.android.internal.policy.impl.PhoneWindow.invalidatePanelMenu(PhoneWindow.java:747)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.Activity.invalidateOptionsMenu(Activity.java:2595)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.FragmentManagerImpl.invalidateOptionsMenu(FragmentManager.java:1950)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.Fragment.setHasOptionsMenu(Fragment.java:901)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at com.kansosystem.fragments.FragmentList.onCreate(FragmentList.java:53)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:796)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.FragmentManagerImpl.moveToState(FragmentManager.java:1035)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.BackStackRecord.run(BackStackRecord.java:635)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.FragmentManagerImpl.execPendingActions(FragmentManager.java:1397)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.FragmentManagerImpl$1.run(FragmentManager.java:426)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.os.Handler.handleCallback(Handler.java:615)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.os.Handler.dispatchMessage(Handler.java:92)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.os.Looper.loop(Looper.java:137)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at android.app.ActivityThread.main(ActivityThread.java:4745)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at java.lang.reflect.Method.invokeNative(Native Method)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at java.lang.reflect.Method.invoke(Method.java:511)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
08-25 09:18:25.840: E/AndroidRuntime(1430):     at dalvik.system.NativeStart.main(Native Method)

Answer 1

首先，确保您的适配器不是null。你可以通过像

这样的日志来做到这一点

Log.d("tag","mListAdapter="+mListAdapter);
mListAdapter.getFilter().filter(newText);

然后检查logcat以查看mListAdapter是否给出了mListAdapter=null。如果是这样，问题是你的适配器。

其次，转到自定义listadapter类中的getfilter方法，并确保您的过滤器不会返回null。必须返回您的过滤器。

切换片段时，Android Nullpointer异常onQueryTextChange

1 个答案: