安卓简易版图片异步加载

来源：互联网发布：java过滤器配置编辑：程序博客网时间：2024/04/27 16:38

配合上一篇的viewpager，加上简易版图片异步加载

public class DownloadImage implements Runnable {    private final int BUFFER_SIZE = 512;    private Activity context;    private String filePath;    private String ImageName;    private ImageView image;    private String url;    private boolean isDownload;    /**     * @param context     * @param filePath   图片路径     * @param ImageName  图片名字     * @param url        图片地址     * @param image      控件     * @param isDownload 是否需要下载     */    public DownloadImage(Activity context, String filePath, String ImageName, String url, ImageView image, boolean            isDownload) {        this.context = context;        this.filePath = filePath;        this.url = url;        this.ImageName = ImageName;        this.image = image;        this.isDownload = isDownload;    }    @Override    public void run() {        try {            if (isDownload) {                saveToFile();            }            while (FileUtil.exist(filePath + ImageName + ".data")) {                context.runOnUiThread(new Runnable() {                    @Override                    public void run() {                        image.setImageBitmap(getLoacalBitmap(filePath + ImageName + ".data"));                    }                });            }        } catch (Exception e) {            e.printStackTrace();        }    }    public void saveToFile() throws Exception {        if (!FileUtil.exist(filePath + ImageName + ".data")) {            File fileTemp = new File(filePath, ImageName + ".temp");            if (fileTemp.exists())                fileTemp.delete();            if (FileUtil.createFile(filePath, ImageName + ".temp")) {                FileOutputStream fos;                BufferedInputStream bis;                byte[] buf = new byte[BUFFER_SIZE];                int size;                bis = new BufferedInputStream(HttpClientTools.download(url));                fos = new FileOutputStream(fileTemp);                while ((size = bis.read(buf)) != -1) {                    fos.write(buf, 0, size);                }                FileUtil.renameTo(filePath + ImageName + ".temp", filePath + ImageName + "" +                        ".data");                fos.flush();                fos.close();                bis.close();            }        }    }    public static Bitmap getLoacalBitmap(String url) {        try {            FileInputStream fis = new FileInputStream(url);            return BitmapFactory.decodeStream(fis); // /把流转化为Bitmap图片        } catch (FileNotFoundException e) {            e.printStackTrace();            return null;        }    }}

isDownload是用来下载viewpager中多创建的两张图片，为了使滑动效果看起来更真实

简易图，第三张回到第一张的，向右滑动，显示的是第五个page，松手跳到第二个page，这个isDownload就是处理头尾两张，没必要重复下载图片。

if (FileUtil.exist(filePath + "/" + bean.getImageName() + ".data")) {                image.setImageBitmap(DownloadImage.getLoacalBitmap(filePath + bean.getImageName() + ".data"));                image.setOnClickListener(new OnClickListener() {                    @Override                    public void onClick(View v) {                        callBack.click(bean);                    }                });            } else {                image.setBackgroundResource(bean.getDefaultId());                if (bean.getUrl() != null) {                    image.setOnClickListener(new OnClickListener() {                        @Override                        public void onClick(View v) {                            callBack.click(bean);                        }                    });                    new Thread(new DownloadImage(context, filePath, bean.getImageName(), bean.getUrl(), image,                            isDownload)).start();                }            }

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