空指针异常显示在操作栏夏洛克库

Question

我想实现Sherlock动作栏的搜索视图小部件。我的问题是OnOptionItemSelected的搜索视图项目。我在库活动中得到一个空指针异常。

菜单xml:

<item android:id="@+id/menu_search"
      android:actionViewClass="com.actionbarsherlock.widget.SearchView"
      android:icon="@android:drawable/ic_menu_search"
/>

选项菜单代码片段:

public boolean onCreateOptionsMenu(Menu menu) 
{
    MenuInflater inflater = getSupportMenuInflater();
    inflater.inflate(R.menu.tvguide_menu, menu);
    MenuItem mSearch = menu.findItem(R.id.menu_search);
    searchView = new SearchView(getSupportActionBar().getThemedContext());
    searchView.setQueryHint("Search for countries…");
    searchView.setOnQueryTextListener(this);
    mSearch.setActionView(searchView);
    mSearch.setShowAsAction(MenuItem.SHOW_AS_ACTION_IF_ROOM |
            MenuItem.SHOW_AS_ACTION_COLLAPSE_ACTION_VIEW);
}

我得到一个强制关闭点击搜索android。我已经在下面分享了我的日志

04-17 15:10:08.508: E/AndroidRuntime(23283): FATAL EXCEPTION: main
04-17 15:10:08.508: E/AndroidRuntime(23283): java.lang.NullPointerException
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.view.menu.MenuItemImpl.toString(MenuItemImpl.java:490)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at java.lang.StringBuilder.append(StringBuilder.java:202)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.actionbarsherlock.app.SherlockFragmentActivity.onMenuItemSelected(SherlockFragmentActivity.java:201)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:953)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.view.menu.MenuBuilder.dispatchMenuItemSelected(MenuBuilder.java:735)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:149)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:874)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.view.menu.ActionMenuView.invokeItem(ActionMenuView.java:491)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.view.menu.ActionMenuItemView.onClick(ActionMenuItemView.java:110)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at android.view.View.performClick(View.java:3511)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at android.view.View$PerformClick.run(View.java:14105)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at android.os.Handler.handleCallback(Handler.java:605)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at android.os.Handler.dispatchMessage(Handler.java:92)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at android.os.Looper.loop(Looper.java:137)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at android.app.ActivityThread.main(ActivityThread.java:4438)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at java.lang.reflect.Method.invokeNative(Native Method)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at java.lang.reflect.Method.invoke(Method.java:511)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:784)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:551)
04-17 15:10:08.508: E/AndroidRuntime(23283):    at dalvik.system.NativeStart.main(Native Method)

Answer 1

问题是您的Menu项目没有指定标题，并且在行中:

@Override
public final boolean onMenuItemSelected(int featureId, android.view.MenuItem item) {
    if (BuildConfig.DEBUG) Log.d(TAG, "[onMenuItemSelected] featureId: " 
           + featureId + ", item: " + item);
    ...
}

item将采用toString()方法:

@Override
public String toString() {
    return mTitle.toString();
}

将抛出一个NullPointerException。一个简单的解决方法，直到它被修复是使用:

android:title=""

为您的MenuItem .

同样，这不会发生在您的应用程序的发行版上。

Answer 2

这是ActionBarSherlock 4.3.0版本的一个bug，我用这种方式修复了它(你需要注释ActionBarSherlock/src/com/actionbarsherlock/app/SherlockFragmentActivity.java的第201行:

--- a/actionbarsherlock/src/com/actionbarsherlock/app/SherlockFragmentActivity.java
+++ b/actionbarsherlock/src/com/actionbarsherlock/app/SherlockFragmentActivity.java
@@ -198,7 +198,7 @@ public class SherlockFragmentActivity extends Watson implements OnActionModeStar
     @Override
     public final boolean onMenuItemSelected(int featureId, android.view.MenuItem item) {
-        if (BuildConfig.DEBUG) Log.d(TAG, "[onMenuItemSelected] featureId: " + featureId + ", item: " + item);
+       // if (BuildConfig.DEBUG) Log.d(TAG, "[onMenuItemSelected] featureId: " + featureId + ", item: " + item);
         if (featureId == Window.FEATURE_OPTIONS_PANEL && !mIgnoreNativeSelected) {
             mIgnoreNativeSelected = true;

Answer 3

如果有人面临这个问题，并希望创建没有标题的菜单项，这个nullpointerexception可以通过简单地修改com/android/internal/view/menu/MenuItemImpl类中的toString()方法来解决，从actionbarsherlock源代码中返回之前做一个空字符串检查:

@Override
public String toString() {
    return (mTitle != null)? mTitle.toString(): "";
}