ListView中ImageView滚动时图片消失及ListView对象显隐问题求助

Hey there! Let's break down your two ListView problems and solve them with practical fixes, tailored to your existing IzahAdapter code.

The key here is to control visibility via your data model (not directly manipulating views, since ListView reuses views aggressively). Here's how to implement it step by step:

Step 1: Add a visibility flag to your data model #

Update your IzahVeriModeli class to track whether each item should be visible:

public class IzahVeriModeli {
    // Your existing fields (e.g., text, image URL)
    private boolean isVisible = true; // Default to visible

    // Getter and Setter
    public boolean isVisible() {
        return isVisible;
    }

    public void setVisible(boolean visible) {
        isVisible = visible;
    }
}

Step 2: Update your Adapter's getView() method #

Modify the getView() logic to respect the visibility flag and handle view reuse correctly:

@Override
public View getView(int position, View convertView, ViewGroup parent) {
    // Initialize LayoutInflater if null
    if (layoutInflater == null) {
        layoutInflater = (LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
    }

    // Reuse view or inflate new one
    if (convertView == null) {
        convertView = layoutInflater.inflate(R.layout.your_item_layout, parent, false);
        Holder = new holder();
        // Initialize your holder views here (e.g., Holder.imageView = convertView.findViewById(R.id.item_image);)
        convertView.setTag(Holder);
    } else {
        Holder = (holder) convertView.getTag();
    }

    IzahVeriModeli currentItem = list.get(position);

    // Set visibility based on the model's flag
    if (currentItem.isVisible()) {
        convertView.setVisibility(View.VISIBLE);
        // Bind your data to views here (e.g., Holder.textView.setText(currentItem.getSomeText());)
    } else {
        convertView.setVisibility(View.GONE);
        // Clear view content to avoid reuse issues
        // Holder.textView.setText("");
        // Holder.imageView.setImageDrawable(null);
    }

    return convertView;
}

Step 3: Trigger visibility changes #

To show/hide an item, update the model and notify the adapter:

// Example: Hide the 2nd item (index 1)
list.get(1).setVisible(false);
adapter.notifyDataSetChanged();

This issue almost always stems from nested scroll containers (ListView + ScrollView) causing layout calculation bugs and view reuse issues. Here are the best fixes:

Option 1: Remove ScrollView nesting (RECOMMENDED) #

Android doesn't support nested scroll containers well. Instead, add your static content (above/below ListView) as a header/footer to the ListView:

// Add a header to your ListView
View headerView = getLayoutInflater().inflate(R.layout.your_header_layout, yourListView, false);
yourListView.addHeaderView(headerView);

// Add a footer if needed
View footerView = getLayoutInflater().inflate(R.layout.your_footer_layout, yourListView, false);
yourListView.addFooterView(footerView);

Option 2: Fix the nested layout if you must keep it #

If you can't remove the ScrollView, fix the ListView's height calculation and image loading:

a. Custom ListView to calculate full height

Create a custom ListView that ignores scroll limits and calculates its full height:

public class NonScrollListView extends ListView {
    public NonScrollListView(Context context) {
        super(context);
    }

    public NonScrollListView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public NonScrollListView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        // Force ListView to measure all items' total height
        int expandSpec = MeasureSpec.makeMeasureSpec(Integer.MAX_VALUE >> 2, MeasureSpec.AT_MOST);
        super.onMeasure(widthMeasureSpec, expandSpec);
    }
}

Use this NonScrollListView in your XML layout instead of the default ListView.

b. Fix image loading for view reuse

If using a library like Glide/Picasso (always recommended for image loading), ensure you bind images correctly to avoid reuse bugs:

// Example with Glide in your Adapter's getView()
Glide.with(context)
     .load(currentItem.getImageUrl()) // Your image URL/path
     .placeholder(R.drawable.placeholder_image) // Loading placeholder
     .error(R.drawable.error_image) // Fallback for failed loads
     .into(Holder.imageView);

If loading images manually, use the View's tag to avoid old loads overwriting new content:

// Manual image loading with tag check
Holder.imageView.setTag(currentItem.getImageUrl());

new AsyncTask<String, Void, Bitmap>() {
    @Override
    protected Bitmap doInBackground(String... params) {
        // Your bitmap loading logic here
        return loadBitmapFromUrl(params[0]);
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        // Only set bitmap if the view's tag matches the current item's URL
        if (Holder.imageView.getTag().equals(currentItem.getImageUrl())) {
            Holder.imageView.setImageBitmap(bitmap);
        }
    }
}.execute(currentItem.getImageUrl());

内容的提问来源于stack exchange，提问作者Coşkun Cengiz