我正在使用 Room DataBase，并嘗試將影像粘貼到 RecyclerView 中。但是，當我嘗試將資料檢索到配接器類時，我
You cannot start a load on a not yet attached View or a Fragment where getActivity() returns null (which usually occurs when getActivity() is called before the Fragment is attached or after the Fragment is destroyed).
在其他主題中看到了有關 isAdded() 方法的資訊，但我無法在 Adapter 類中使用它
這是我來自 parentClass 的 clickListener
ARB.contRem.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if(ARB.remText.getText().toString().equals("")){
ARB.err.setText("errCode");
}
else if(ARB.dateFromCalendar.getText().toString().equals("")){
ARB.err.setText("errCode");
}
else {
Bitmap bitmap = ((BitmapDrawable)ARB.addImageRem.getDrawable()).getBitmap();
Uri uri = getImageUri(getContext(), bitmap);
ARVM.addReminder(ARB.remText.getText().toString(),
ARB.dateFromCalendar.getText().toString(),
false,
uri.toString());
Navigation.findNavController(v).popBackStack();
}
}
});
這是來自 AdapterClass
@Override
public void onBindViewHolder(@NonNull reminderViewHolder holder, int position) {
Uri uri = Uri.parse(rems.get(position).getImages());
Glide.with(ct).load(new File(uri.getPath())).into(holder.binding.imageView);
holder.binding.textrow.setText(rems.get(position).getTextRem());
holder.binding.daterow.setText(rems.get(position).getDateRem());
holder.binding.isdone.setChecked(rems.get(position).isDone());
}
這就是我嘗試檢索資料后得到的
2021-09-23 15:28:10.308 5391-5391/com.example.rempractice E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.example.rempractice, PID: 5391
java.lang.NullPointerException: You cannot start a load on a not yet attached View or a Fragment where getActivity() returns null (which usually occurs when getActivity() is called before the Fragment is attached or after the Fragment is destroyed).
at com.bumptech.glide.util.Preconditions.checkNotNull(Preconditions.java:29)
at com.bumptech.glide.Glide.getRetriever(Glide.java:769)
at com.bumptech.glide.Glide.with(Glide.java:801)
at com.example.rempractice.project.View.adapters.reminderAdapter.onBindViewHolder(reminderAdapter.java:40)
at com.example.rempractice.project.View.adapters.reminderAdapter.onBindViewHolder(reminderAdapter.java:19)
at androidx.recyclerview.widget.RecyclerView$Adapter.onBindViewHolder(RecyclerView.java:7065)
at androidx.recyclerview.widget.RecyclerView$Adapter.bindViewHolder(RecyclerView.java:7107)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryBindViewHolderByDeadline(RecyclerView.java:6012)
at androidx.recyclerview.widget.RecyclerView$Recycler.tryGetViewHolderForPositionByDeadline(RecyclerView.java:6279)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6118)
at androidx.recyclerview.widget.RecyclerView$Recycler.getViewForPosition(RecyclerView.java:6114)
at androidx.recyclerview.widget.LinearLayoutManager$LayoutState.next(LinearLayoutManager.java:2303)
at androidx.recyclerview.widget.LinearLayoutManager.layoutChunk(LinearLayoutManager.java:1627)
at androidx.recyclerview.widget.LinearLayoutManager.fill(LinearLayoutManager.java:1587)
at androidx.recyclerview.widget.LinearLayoutManager.onLayoutChildren(LinearLayoutManager.java:665)
at androidx.recyclerview.widget.RecyclerView.dispatchLayoutStep2(RecyclerView.java:4134)
at androidx.recyclerview.widget.RecyclerView.dispatchLayout(RecyclerView.java:3851)
at androidx.recyclerview.widget.RecyclerView.onLayout(RecyclerView.java:4404)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1873)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at androidx.constraintlayout.widget.ConstraintLayout.onLayout(ConstraintLayout.java:1873)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.LinearLayout.setChildFrame(LinearLayout.java:1829)
at android.widget.LinearLayout.layoutVertical(LinearLayout.java:1673)
at android.widget.LinearLayout.onLayout(LinearLayout.java:1582)
at android.view.View.layout(View.java:22844)
at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.widget.FrameLayout.layoutChildren(FrameLayout.java:332)
at android.widget.FrameLayout.onLayout(FrameLayout.java:270)
at com.android.internal.policy.DecorView.onLayout(DecorView.java:784)
at android.view.View.layout(View.java:22844)
2021-09-23 15:28:10.308 5391-5391/com.example.rempractice E/AndroidRuntime: at android.view.ViewGroup.layout(ViewGroup.java:6389)
at android.view.ViewRootImpl.performLayout(ViewRootImpl.java:3470)
at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:2938)
at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1952)
at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:8171)
at android.view.Choreographer$CallbackRecord.run(Choreographer.java:972)
at android.view.Choreographer.doCallbacks(Choreographer.java:796)
at android.view.Choreographer.doFrame(Choreographer.java:731)
at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:957)
at android.os.Handler.handleCallback(Handler.java:938)
at android.os.Handler.dispatchMessage(Handler.java:99)
at android.os.Looper.loop(Looper.java:223)
at android.app.ActivityThread.main(ActivityThread.java:7656)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:592)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:947)
uj5u.com熱心網友回復：
在這種情況下，我通常會將對主機片段或其背景關系的參考傳遞給配接器建構式以保留它并在 Glide 中需要時使用它，如下所示：
public class MyAdapter extends RecyclerView.Adapter<reminderViewHolder > {
private final Fragment hostFragment;
public MyAdapter (Fragment m_hostFragment) {
this.hostFragment = m_hostFragment;
}
...
public void onBindViewHolder(@NonNull reminderViewHolder holder, int position) {
Uri uri = Uri.parse(rems.get(position).getImages());
Glide.with(hostFragment).load( uri).into(holder.binding.imageView);
}
}
當我在我的片段中初始化我的配接器時，我只會傳遞我的片段參考
public class MyFragment extends Fragment {
...
@Override
public void onViewCreated(@Nullable Bundle savedInstanceState) {
...
MyAdapter pagesAdapter = new MyAdapter (this);
...
}
...
}
更新我們在評論中談論的內容
這取決于您從 getImages 方法回傳的內容。我不知道你在那里回傳什么，但你應該一次只回傳一個只屬于一個影像的字串。
RecyclerView 是一個串列，每一行/每一列代表一個不同的持有者，對于每個持有者 RecyclerView 呼叫 onBindHolder 來初始化它，如果你想顯示多張影像，你應該在不同的持有者中顯示每一個，并且 RecyclerView 將多次呼叫 onBindHolder 直到你所有的arraylist 資料在螢屏上。
因此，假設您的資料 ArrayList 如果是 string 型別，其中每個專案都包含一個影像 uri 字串，那么將 uri 字串放入 one 中就足夠了onBindViewHolder。
public class MyAdapter extends RecyclerView.Adapter<reminderViewHolder>{
private final Fragment hostFragment;
List<String> photos ;
public MyAdapter (Fragment m_hostFragment,List<String> photos) {
this.hostFragment = m_hostFragment;
this.photos = photos;
}
...
public void onBindViewHolder(@NonNull reminderViewHolder holder, int position) {
String photo_Uri = photos.get(position);
Glide.with(hostFragment).load(photo_Uri).into(holder.binding.imageView);
}
@Override
public int getItemCount() {
return photos.size();
}
}
并且您的 RecyclerView 將在 getItemCount 回傳時多次呼叫 onBindViewHolder 來表示您的所有資料。
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標籤：爪哇 安卓 android-fragments android-room
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