Java Android CardsLib-NullPointerException OnLongCardClickListener多选项模式
我正在使用Android在我的片段中生成一个卡片列表。我已经把清单做好了,这里没问题 现在,我按照教程()将多选模式添加到我的列表中,这是使用长点击/单击选择选择多张卡。但是我得到了一个Java Android CardsLib-NullPointerException OnLongCardClickListener多选项模式,java,android,nullpointerexception,android-cards,Java,Android,Nullpointerexception,Android Cards,我正在使用Android在我的片段中生成一个卡片列表。我已经把清单做好了,这里没问题 现在,我按照教程()将多选模式添加到我的列表中,这是使用长点击/单击选择选择多张卡。但是我得到了一个NullPointerException 这是我的stacktrace: FATAL EXCEPTION: main Process: com.mypackage.android.design.appdesgin, PID: 18937 java.lang.NullPointerException at
NullPointerException
这是我的stacktrace:
FATAL EXCEPTION: main
Process: com.mypackage.android.design.appdesgin, PID: 18937
java.lang.NullPointerException
at it.gmariotti.cardslib.library.internal.multichoice.MultiChoiceAdapterHelperBase.onItemSelectedStateChanged(MultiChoiceAdapterHelperBase.java:293)
at it.gmariotti.cardslib.library.internal.multichoice.MultiChoiceAdapterHelperBase.onCreateActionMode(MultiChoiceAdapterHelperBase.java:255)
at it.gmariotti.cardslib.library.internal.CardArrayMultiChoiceAdapter.onCreateActionMode(CardArrayMultiChoiceAdapter.java:131)
at com.mypackage.android.design.appdesgin.cards.MyCardArrayMultiChoiceAdapter.onCreateActionMode(MyCardArrayMultiChoiceAdapter.java:31)
at com.android.internal.policy.impl.PhoneWindow$DecorView$ActionModeCallbackWrapper.onCreateActionMode(PhoneWindow.java:3011)
at com.android.internal.app.ActionBarImpl$ActionModeImpl.dispatchOnCreate(ActionBarImpl.java:909)
at com.android.internal.app.ActionBarImpl.startActionMode(ActionBarImpl.java:453)
at android.app.Activity.onWindowStartingActionMode(Activity.java:5005)
at com.android.internal.policy.impl.PhoneWindow$DecorView.startActionMode(PhoneWindow.java:2636)
at android.app.Activity.startActionMode(Activity.java:4987)
at it.gmariotti.cardslib.library.internal.multichoice.MultiChoiceAdapterHelperBase.startActionMode(MultiChoiceAdapterHelperBase.java:239)
at it.gmariotti.cardslib.library.internal.CardArrayMultiChoiceAdapter.startActionMode(CardArrayMultiChoiceAdapter.java:117)
at com.mypackage.android.design.appdesgin.fragments.CardLocalBackupsFragment$1.onLongClick(CardLocalBackupsFragment.java:152)
at it.gmariotti.cardslib.library.view.CardView$5.onLongClick(CardView.java:533)
at android.view.View.performLongClick(View.java:4481)
at android.view.View$CheckForLongPress.run(View.java:18425)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5081)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:791)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:607)
at dalvik.system.NativeStart.main(Native Method)
空指针位于此处:
protected void onItemSelectedStateChanged(ActionMode mode) {
int count = mAdapterView.getCheckedItemCount(); // mAdapterView is NULL
if (count > 0) {
Resources res = mAdapterView.getResources();
String mTitleSelected = res.getQuantityString(R.plurals.card_selected_items, count, count);
mode.setTitle(mTitleSelected);
}
}
但此代码属于属于属于cardlib代码的一部分的MultiChoiceAdapterHelperBase
在stacktrace之后,它会导致这个类(我从教程中复制了这个类),MyCardArrayMultiChoiceAdapter
,它有这个代码(NPE正在调用super ononCreateActionMode
)
公共类MyCardArrayMultiChoiceAdapter扩展了CardArrayMultiChoiceAdapter{
私人行动模式;
公共MyCardArrayMultiChoiceAdapter(上下文、列表卡){
超级(上下文、卡片);
}
@凌驾
公共布尔onCreateActionMode(ActionMode模式,菜单){
//调用super方法非常重要
super.onCreateActionMode(mode,menu);//这是第31行,在我的stacktrace中显示
mActionMode=mode;//管理片段/活动中的模式
//如果你想给菜单充气
MenuInflater充气器=模式。getMenuInflater();
充气机。充气(R.menu.carddemo_multichoice,menu);
返回true;
}
@凌驾
公共布尔onPrepareActionMode(操作模式,菜单){
返回false;
}
@凌驾
公共布尔值onActionItemClicked(ActionMode模式,菜单项){
//if(item.getItemId()==R.id.menu\u共享){
//Toast.makeText(getContext(),“Share;”+formatCheckedCard(),Toast.LENGTH_SHORT).show();
//返回true;
// }
if(item.getItemId()==R.id.menu\u放弃){
丢弃SelectedItems(模式);
返回true;
}
返回false;
}
@凌驾
public void onItemCheckedStateChanged(操作模式、整数位置、长id、布尔值选中、CardView CardView、Card Card){
Toast.makeText(getContext(),“单击;”+位置+“-”+选中,Toast.LENGTH\u SHORT).show();
}
私有void丢弃SelectedItems(操作模式){
ArrayList items=getSelectedCards();
用于(卡片项目:项目){
删除(项目);
}
mode.finish();
}
私有字符串formatCheckedCard(){
SparseBooleanArray checked=mCardListView.GetCheckEditePositions();
StringBuffer sb=新的StringBuffer();
对于(int i=0;i
有人知道为什么会出现这个空点异常吗?或者,在我的cardslist中实现多选模式有什么错
如果需要在此处添加更多代码,请告诉我,我将编辑此问题。发现问题
我仍然在使用包含列表的片段上的cardarayadapter
。我从CardArrayAdapter
移动到CardArrayMultiChoiceAdapter
,它工作正常:)
所以我(在我的片段上)有这样的东西:
本教程中包含:
如果您想要一个内置多选模式的卡片列表
功能您可以使用CardArrayMultiChoiceAdapter
此类扩展CardArrayAdapter并保留其所有功能
我一直得到相同的异常,只是我已经在使用
CardArrayMultiChoiceAdapter
事实证明,我使用的是常规的
ListView
而不是CardListView
这一事实导致了我的问题。是否有任何Android卡UI库提供了卡之间交换的方法?@Nevaeh你应该提出一个新的问题。我不知道CardsLib是否能做到这一点,我从来都不需要这个功能。对不起,我没办法。
public class MyCardArrayMultiChoiceAdapter extends CardArrayMultiChoiceAdapter {
private ActionMode mActionMode;
public MyCardArrayMultiChoiceAdapter(Context context, List<Card> cards) {
super(context, cards);
}
@Override
public boolean onCreateActionMode(ActionMode mode, Menu menu) {
//It is very important to call the super method
super.onCreateActionMode(mode, menu); // This is line 31 where it says in my stacktrace
mActionMode = mode; // to manage mode in your Fragment/Activity
//If you would like to inflate your menu
MenuInflater inflater = mode.getMenuInflater();
inflater.inflate(R.menu.carddemo_multichoice, menu);
return true;
}
@Override
public boolean onPrepareActionMode(ActionMode mode, Menu menu) {
return false;
}
@Override
public boolean onActionItemClicked(ActionMode mode, MenuItem item) {
// if (item.getItemId() == R.id.menu_share) {
// Toast.makeText(getContext(), "Share;" + formatCheckedCard(), Toast.LENGTH_SHORT).show();
// return true;
// }
if (item.getItemId() == R.id.menu_discard) {
discardSelectedItems(mode);
return true;
}
return false;
}
@Override
public void onItemCheckedStateChanged(ActionMode mode, int position, long id, boolean checked, CardView cardView, Card card) {
Toast.makeText(getContext(), "Click;" + position + " - " + checked, Toast.LENGTH_SHORT).show();
}
private void discardSelectedItems(ActionMode mode) {
ArrayList<Card> items = getSelectedCards();
for (Card item : items) {
remove(item);
}
mode.finish();
}
private String formatCheckedCard() {
SparseBooleanArray checked = mCardListView.getCheckedItemPositions();
StringBuffer sb = new StringBuffer();
for (int i = 0; i < checked.size(); i++) {
if (checked.valueAt(i) == true) {
sb.append("\nPosition=" + checked.keyAt(i));
}
}
return sb.toString();
}
}
private CardArrayAdapter cardArrayAdapter; // comment this one
private MyCardArrayMultiChoiceAdapter cardArrayAdapter; // use this one!