图像在列表视图中随机播放.滚动时 [英] Image shuffles in list view. when scrolling

问题描述

发生的事情是，在滚动列表时，每个项目上加载的图像都会被打乱，并且每个项目的化身都将转到下一个项目.我不知道我是否很清楚，但我会与图像一起显示 我的自定义适配器类

What happens is that when scrolling the list, the images that were loaded on each item are shuffled, and the avatar of each item going to the next item ends. I do not know if I'm being clear but I will show with the image my custom adapter class

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;

public class CustomListAdapter extends BaseAdapter {
    private ArrayList listData;
    private LayoutInflater layoutInflater;

    public CustomListAdapter(Context context, ArrayList listData) {
        this.listData = listData;
        layoutInflater = LayoutInflater.from(context);
    }

    @Override
    public int getCount() {
        return listData.size();
    }

    @Override
    public Object getItem(int position) {
        return listData.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = layoutInflater.inflate(R.layout.list_row_layout, null);
            holder = new ViewHolder();
            holder.headlineView = (TextView) convertView.findViewById(R.id.title);
            holder.reporterNameView = (TextView) convertView.findViewById(R.id.reporter);
            holder.reportedDateView = (TextView) convertView.findViewById(R.id.date);
            holder.imageView = (ImageView) convertView.findViewById(R.id.thumbImage);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        NewsItem newsItem = (NewsItem) listData.get(position);
        holder.headlineView.setText(newsItem.getHeadline());
        holder.reporterNameView.setText("By, " + newsItem.getReporterName());
        holder.reportedDateView.setText(newsItem.getDate());
        if (holder.imageView != null) {
            new ImageDownloaderTask(holder.imageView).execute(newsItem.getUrl());
        }
        return convertView;
    }

    static class ViewHolder {
        TextView headlineView;
        TextView reporterNameView;
        TextView reportedDateView;
        ImageView imageView;
    }
}

我的新闻类

public class NewsItem {

    private String headline;
    private String reporterName;
    private String date;
    private String url;

    public String getUrl() {
        return url;
    }

    public void setUrl(String url) {
        this.url = url;
    }

    public String getHeadline() {
        return headline;
    }

    public void setHeadline(String headline) {
        this.headline = headline;
    }

    public String getReporterName() {
        return reporterName;
    }

    public void setReporterName(String reporterName) {
        this.reporterName = reporterName;
    }

    public String getDate() {
        return date;
    }

    public void setDate(String date) {
        this.date = date;
    }

    @Override
    public String toString() {
        return "[ headline=" + headline + ", reporter Name=" + reporterName + " , date=" + date + "]";
    }
}

我的imageDownloaderTask

my imageDownloaderTask

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.drawable.Drawable;
import android.os.AsyncTask;
import android.util.Log;
import android.widget.ImageView;

import org.apache.http.HttpStatus;

import java.io.InputStream;
import java.lang.ref.WeakReference;
import java.net.HttpURLConnection;
import java.net.URL;

class ImageDownloaderTask extends AsyncTask<String, Void, Bitmap> {
    private final WeakReference<ImageView> imageViewReference;

    public ImageDownloaderTask(ImageView imageView) {
        imageViewReference = new WeakReference<ImageView>(imageView);
    }

    @Override
    protected Bitmap doInBackground(String... params) {
        return downloadBitmap(params[0]);
    }

    @Override
    protected void onPostExecute(Bitmap bitmap) {
        if (isCancelled()) {
            bitmap = null;
        }

        if (imageViewReference != null) {
            ImageView imageView = imageViewReference.get();
            if (imageView != null) {
                if (bitmap != null) {
                    imageView.setImageBitmap(bitmap);
                } else {
                    Drawable placeholder = imageView.getContext().getResources().getDrawable(R.drawable.placeholder);
                    imageView.setImageDrawable(placeholder);
                }
            }
        }
    }
    private Bitmap downloadBitmap(String url) {
        HttpURLConnection urlConnection = null;
        try {
            URL uri = new URL(url);
            urlConnection = (HttpURLConnection) uri.openConnection();
            int statusCode = urlConnection.getResponseCode();
            if (statusCode != HttpStatus.SC_OK) {
                return null;
            }

            InputStream inputStream = urlConnection.getInputStream();
            if (inputStream != null) {
                Bitmap bitmap = BitmapFactory.decodeStream(inputStream);
                return bitmap;
            }
        } catch (Exception e) {
            urlConnection.disconnect();
            Log.w("ImageDownloader", "Error downloading image from " + url);
        } finally {
            if (urlConnection != null) {
                urlConnection.disconnect();
            }
        }
        return null;
    }
}

推荐答案

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;

import java.util.ArrayList;

public class CustomListAdapter extends BaseAdapter {
    private ArrayList listData;
    private LayoutInflater layoutInflater;

    public CustomListAdapter(Context context, ArrayList listData) {
        this.listData = listData;
        layoutInflater = LayoutInflater.from(context);
    }

    @Override
    public int getCount() {
        return listData.size();
    }

    @Override
    public Object getItem(int position) {
        return listData.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        ViewHolder holder;
        if (convertView == null) {
            convertView = layoutInflater.inflate(R.layout.list_row_layout, null);
            holder = new ViewHolder();
            holder.headlineView = (TextView) convertView.findViewById(R.id.title);
            holder.reporterNameView = (TextView) convertView.findViewById(R.id.reporter);
            holder.reportedDateView = (TextView) convertView.findViewById(R.id.date);
            holder.imageView = (ImageView) convertView.findViewById(R.id.thumbImage);
            convertView.setTag(holder);
        } else {
            holder = (ViewHolder) convertView.getTag();
        }

        NewsItem newsItem = (NewsItem) listData.get(position);
        holder.headlineView.setText(newsItem.getHeadline());
        holder.reporterNameView.setText("By, " + newsItem.getReporterName());
        holder.reportedDateView.setText(newsItem.getDate());

        Drawable placeholder = holder.imageView.getContext().getResources().getDrawable(R.drawable.placeholder;
                holder.imageView.setImageDrawable(placeholder);       

            new ImageDownloaderTask(holder.imageView).execute(newsItem.getUrl());

        return convertView;
    }

    static class ViewHolder {
        TextView headlineView;
        TextView reporterNameView;
        TextView reportedDateView;
        ImageView imageView;
    }

这篇关于图像在列表视图中随机播放.滚动时的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持IT屋！