使用 MutableLiveData 和具有多个图像的 LiveData 实现 ViewModel
问题描述 投票：0回答：0
下面的代码使我能够从手机图片库中最多选择 4 张图片。但是，我需要有关视图模型代码的帮助。如果选择了一张图像并且手机配置发生了变化，则该图像会保留下来。但是，如果选择了多张图像，则只有一张图像会保留，所有其他图像都会消失。我需要帮助才能知道我在 viewmodel 代码上做错了什么。在没有视图模型的情况下，所有其他代码都按预期运行良好。添加视图模型以在手机配置更改时为图像添加持久性。我在下面附上了我的代码。
这是选择图像的java代码
'''
public class MakingFamzFragment extends Fragment {
ActivityResultLauncher<PickVisualMediaRequest> pickMedia = registerForActivityResult(new ActivityResultContracts.PickMultipleVisualMedia(4),
new ActivityResultCallback<List<Uri>>() {
@Override
public void onActivityResult(List<Uri> result) {
Intent intent = new Intent();
Intent intent2 = new Intent();
Intent intent3 = new Intent();
Intent intent4 = new Intent();
if(result.size() == 1){
// Code for when only one picture is picked
//Capturing the activity result Uri in the Intent
intentOne = intent.setData(result.get(0));
//Create ContentResolver to convert the Uri to Bitmap
cr = requireContext().getContentResolver();
try {
bitmapOne = MediaStore.Images.Media.getBitmap(cr, intentOne.getData());
} catch (IOException e) {
e.printStackTrace();
}
if (isbitmapOne(bitmapOne)) {
//Capturing the first image in ImageViewOne using Glide
ImageViewOne = binding.editBeforePostingOne;
ImageViewOne.setImageBitmap(bitmapOne);
Glide.with(requireActivity())
.load(bitmapOne)
.centerCrop()
.into(ImageViewOne);
ImageViewOne.setVisibility(View.VISIBLE);
viewModel.setImageL(Collections.singletonList(bitmapOne));
}
}else if(result.size() == 2){
// Codes for only when two pictures are picked
intentOne = intent.setData(result.get(0));
intentTwo = intent2.setData(result.get(1));
//Create ContentResolver to convert the Uris to Bitmap
cr = requireContext().getContentResolver();
try {
bitmapOne = MediaStore.Images.Media.getBitmap(cr, intentOne.getData());
bitmapTwo = MediaStore.Images.Media.getBitmap(cr, intentTwo.getData());
} catch (IOException e) {
e.printStackTrace();
}
if (isbitmapOne(bitmapOne) && isbitmapTwo(bitmapTwo)) {
//Capturing the first image in ImageViewOne using Glide
ImageViewOne = binding.editBeforePostingOne;
ImageViewOne.setImageBitmap(bitmapOne);
Glide.with(requireActivity())
.load(bitmapOne)
.centerCrop()
.into(ImageViewOne);
ImageViewOne.setVisibility(View.VISIBLE);
viewModel.setImageL(Collections.singletonList(bitmapOne));
//Capturing the second image in ImageViewTwo using Glide
ImageViewTwo = binding.editBeforePostingTwo;
ImageViewTwo.setImageBitmap(bitmapTwo);
Glide.with(requireActivity())
.load(bitmapTwo)
.centerCrop()
.into(ImageViewTwo);
ImageViewTwo.setVisibility(View.VISIBLE);
viewModel.setImageL(Collections.singletonList(bitmapTwo));
}
}else if(result.size() == 3){
//Codes for only when three pictures are picked
intentOne = intent.setData(result.get(0));
intentTwo = intent2.setData(result.get(1));
intentThree = intent3.setData(result.get(2));
//Create ContentResolver to convert the Uris to Bitmap
cr = requireContext().getContentResolver();
try {
bitmapOne = MediaStore.Images.Media.getBitmap(cr, intentOne.getData());
bitmapTwo = MediaStore.Images.Media.getBitmap(cr, intentTwo.getData());
bitmapThree = MediaStore.Images.Media.getBitmap(cr, intentThree.getData());
} catch (IOException e) {
e.printStackTrace();
}
if (isbitmapOne(bitmapOne) && isbitmapTwo(bitmapTwo) && isbitmapThree(bitmapThree)) {
//Capturing the first image in ImageViewOne using Glide
ImageViewOne = binding.editBeforePostingOne;
ImageViewOne.setImageBitmap(bitmapOne);
Glide.with(requireActivity())
.load(bitmapOne)
.centerCrop()
.into(ImageViewOne);
ImageViewOne.setVisibility(View.VISIBLE);
viewModel.setImageL(Collections.singletonList(bitmapOne));
//Capturing the second image in ImageViewThree using Glide
ImageViewTwo = binding.editBeforePostingTwo;
ImageViewTwo.setImageBitmap(bitmapTwo);
Glide.with(requireActivity())
.load(bitmapTwo)
.centerCrop()
.into(ImageViewTwo);
ImageViewTwo.setVisibility(View.VISIBLE);
viewModel.setImageL(Collections.singletonList(bitmapTwo));
//Capturing the third image in ImageViewThree using Glide
ImageViewThree = binding.editBeforePostingThree;
ImageViewThree.setImageBitmap(bitmapThree);
Glide.with(requireActivity())
.load(bitmapThree)
.centerCrop()
.into(ImageViewThree);
ImageViewThree.setVisibility(View.VISIBLE);
viewModel.setImageL(Collections.singletonList(bitmapThree));
}
}
}
});
@Override
public View onCreateView(@NonNull LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
//Instantiatiate the binding class
binding = FragmentMakingFamzBinding.inflate(getLayoutInflater());
//Instantiate the viewModel class
viewModel = new ViewModelProvider(this.requireActivity()).get(MyViewModel.class);
// binding the multiautocompletetextiview as famzMakinglayout and implement the textcount found in it
//to count the number of text typed in it
fmzMakingLayout = binding.multiAutocompleteTextview;
textCount = binding.textCount;
fmzMakingLayout.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
ch = String.valueOf(fmzMakingLayout.getText().toString().length());
textCount.setText(ch);
System.out.println(ch);
}
@Override
public void afterTextChanged(Editable editable) {
}
});
return binding.getRoot();
}
@Override
public void onViewCreated(@NonNull View view, @Nullable Bundle savedInstanceState) {
super.onViewCreated(view, savedInstanceState);
viewModel.getImage().observe(getViewLifecycleOwner(), new Observer<List<Bitmap>>() {
@Override
public void onChanged(List<Bitmap> bitmap) {
if(bitmap.size() == 1){
bitmapOne = bitmap.get(0);
ImageViewOne = binding.editBeforePostingOne;
ImageViewOne.setImageBitmap(bitmapOne);
Glide.with(requireContext())
.load(bitmapOne)
.centerCrop()
.into(ImageViewOne);
ImageViewOne.setVisibility(View.VISIBLE);
}else if(bitmap.size() == 2) {
bitmapOne = bitmap.get(0);
ImageViewOne = binding.editBeforePostingOne;
ImageViewOne.setImageBitmap(bitmapOne);
Glide.with(requireContext())
.load(bitmapOne)
.centerCrop()
.into(ImageViewOne);
ImageViewOne.setVisibility(View.VISIBLE);
bitmapTwo = bitmap.get(1);
ImageViewTwo = binding.editBeforePostingTwo;
ImageViewTwo.setImageBitmap(bitmapTwo);
Glide.with(requireContext())
.load(bitmapTwo)
.centerCrop()
.into(ImageViewTwo);
ImageViewTwo.setVisibility(View.VISIBLE);
}
}
});
binding.famzingBottomNavigation.setOnItemSelectedListener(new NavigationBarView.OnItemSelectedListener() {
@RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN_MR2)
@Override
public boolean onNavigationItemSelected(@NonNull MenuItem item) {
// Defining local final ids
final int id1 = R.id.famzing_add_pictures;
final int id2 = R.id.famzing_files;
final int id3 = R.id.famzing_emoji;
final int id4 = R.id.famzing_giff;
switch (item.getItemId()) {
case id1:
Intent iGallery = new Intent(Intent.ACTION_PICK);
iGallery.setDataAndType(MediaStore.Images.Media.EXTERNAL_CONTENT_URI, "image/*");
iGallery.putExtra(Intent.EXTRA_ALLOW_MULTIPLE, true);
pickMedia.launch(pick);
Toast.makeText(getContext(), "Add picture selected", Toast.LENGTH_SHORT).show();
break;
case id2:
Toast.makeText(getContext(), "Add files selected", Toast.LENGTH_SHORT).show();
break;
case id3:
Toast.makeText(getContext(), "Add emoji selected", Toast.LENGTH_SHORT).show();
break;
case id4:
Toast.makeText(getContext(), "Add giff selected", Toast.LENGTH_SHORT).show();
break;
}
return false;
}
});
}
}
'''
This is the viewmodel code
---------------------------
'''
public class MyViewModel extends ViewModel {
public MutableLiveData<List<Bitmap>> imageL = new MutableLiveData<>();
public void setImageL(List<Bitmap> bitmapOne){
imageL.postValue(bitmapOne);
}
public LiveData<List<Bitmap>> getImage(){
return imageL;
}
@Override
protected void onCleared() {
super.onCleared();
}
}
'''
这是包含图像视图的片段的 xml 代码
发送到
'''
<?xml version="1.0" encoding="utf-8"?>
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:id="@+id/famz_making_page"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:background="@color/white"
android:orientation="vertical"
tools:context=".MakingFamzFragment">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="90dp"
android:gravity="top"
android:orientation="horizontal"
android:padding="9dp">
<ImageView
android:layout_width="40dp"
android:layout_height="40dp"
android:layout_marginStart="9dp"
android:layout_marginLeft="9dp"
android:background="@mipmap/user_profile_image"
android:contentDescription="@string/profile_picture"
android:gravity="end">
</ImageView>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:orientation="vertical">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="start"
android:layout_marginStart="9dp"
android:layout_marginLeft="9dp"
android:text="@string/profile_name"
android:textSize="12sp">
</TextView>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="start|bottom"
android:layout_marginStart="9dp"
android:layout_marginLeft="9dp"
android:layout_marginBottom="6dp"
android:text="@string/profile_username"
android:textSize="12sp">
</TextView>
</LinearLayout>
</LinearLayout>
<View
android:layout_width="match_parent"
android:layout_height="1dp"
android:layout_marginTop="2dp"
android:background="?android:attr/listDivider">
</View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@color/pink"
android:orientation="vertical">
<TextView
android:id="@+id/text_count"
android:layout_width="39dp"
android:layout_height="15dp"
android:layout_gravity="end"
android:layout_marginTop="2dp"
android:layout_marginEnd="9dp"
android:layout_marginRight="9dp">
</TextView>
<MultiAutoCompleteTextView
android:id="@+id/multi_autocomplete_textview"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="6dp"
android:autoLink="all"
android:background="@color/transparent"
android:bufferType="normal"
android:fitsSystemWindows="true"
android:fontFamily="sans-serif"
android:hint="@string/write_here"
android:linksClickable="true"
android:maxLength="500"
android:padding="8dp"
android:selectAllOnFocus="true"
android:textColorLink="#2596be"
android:textSize="16sp"
tools:ignore="TouchTargetSizeCheck">
</MultiAutoCompleteTextView>
<HorizontalScrollView
android:layout_width="wrap_content"
android:layout_height="wrap_content">
<RelativeLayout
android:id="@+id/relate_make_post_frag"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal">
<ImageView
android:layout_width="200dp"
android:layout_height="150dp"
android:id="@+id/edit_Before_Posting_One"
android:contentDescription="@string/image_number_one"
android:layout_alignParentLeft="true"
android:layout_alignParentStart="true"
android:layout_marginStart="2dp"
android:layout_marginLeft="2dp"
android:layout_marginEnd="2dp"
android:layout_marginRight="2dp"
android:visibility="gone"/>
<ImageView
android:layout_width="200dp"
android:layout_height="150dp"
android:id="@+id/edit_Before_Posting_Two"
android:contentDescription="@string/image_number_two"
android:layout_toRightOf="@id/edit_Before_Posting_One"
android:layout_toEndOf="@id/edit_Before_Posting_One"
android:layout_marginStart="2dp"
android:layout_marginLeft="2dp"
android:layout_marginEnd="2dp"
android:layout_marginRight="2dp"
android:visibility="gone"/>
<ImageView
android:layout_width="200dp"
android:layout_height="150dp"
android:id="@+id/edit_Before_Posting_three"
android:contentDescription="@string/image_number_three"
android:layout_toRightOf="@id/edit_Before_Posting_Two"
android:layout_toEndOf="@id/edit_Before_Posting_Two"
android:layout_marginStart="2dp"
android:layout_marginLeft="2dp"
android:layout_marginEnd="2dp"
android:layout_marginRight="2dp"
android:visibility="gone"/>
<ImageView
android:layout_width="200dp"
android:layout_height="150dp"
android:id="@+id/edit_Before_Posting_Four"
android:contentDescription="@string/image_number_four"
android:layout_toRightOf="@id/edit_Before_Posting_three"
android:layout_toEndOf="@id/edit_Before_Posting_three"
android:layout_marginStart="2dp"
android:layout_marginLeft="2dp"
android:layout_marginEnd="2dp"
android:layout_marginRight="2dp"
android:visibility="gone"/>
</RelativeLayout>
</HorizontalScrollView>
<View
android:layout_width="wrap_content"
android:layout_height="1dp"
android:layout_marginTop="2dp"
android:background="?android:attr/listDivider">
</View>
</LinearLayout>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:foregroundGravity="top"
android:background="@color/white">
<com.google.android.material.bottomnavigation.BottomNavigationView
android:id="@+id/famzing_bottom_navigation"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/makingfamz_elevation"
android:fitsSystemWindows="true"
app:elevation="7dp"
app:itemIconTint="@color/fambuk_green"
app:itemTextColor="@color/fambuk_green"
app:menu="@menu/famz_making_menu">
</com.google.android.material.bottomnavigation.BottomNavigationView>
</LinearLayout>
<View
android:layout_width="wrap_content"
android:layout_height="1dp"
android:layout_marginTop="2dp"
android:background="?android:attr/listDivider">
</View>
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal">
<Button
style="?android:attr/buttonBarButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginEnd="4dp"
android:layout_marginRight="0.1dp"
android:layout_weight="2"
android:background="@drawable/submit_post_button_elevation"
android:text="@string/post_submit_button"
android:textColor="@color/white">
</Button>
<Button
style="?android:attr/buttonBarButtonStyle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginStart="0.1dp"
android:layout_marginLeft="0.1dp"
android:layout_weight="2"
android:background="@drawable/submit_post_button_elevation"
android:text="@string/close_button"
android:textColor="@color/white">
</Button>
</LinearLayout>
<View
android:layout_width="wrap_content"
android:layout_height="1dp"
android:layout_marginTop="2dp"
android:background="?android:attr/listDivider">
</View>
</LinearLayout>
</ScrollView>
'''
这是一张图片被选中时的屏幕截图，当手机旋转时会发生什么
注意：当只选择一张图像时，viewmodel 工作正常。 However, when more than one image is selected, the viewmodel does not work properly. 当我选择两个不同的图像时，出现的两个图像是最后一个被选择的图像。第一个没有出现。当它旋转到横向模式时，一个图像消失，片段上只剩下一个。以下是示例屏幕截图：
How can I write the viewmodel code so that when more than one images are picked and the orientation of the phone is changed, all picked images will not disappear from the phone.
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