gallery加载大量图片时内存溢出的解决方法（一）

这只是我以前开始搞android事留下的代码，发现还是存在问题的，我现在把代码放出来，仅供参考，如没有帮助就不要看了，

Gallery加载大量图片的时候容易内存溢出，但是如果及时回收不用的图片，在使用的时候再重新加载，这样就不会出现内存溢出的现象了，所以一定要将加载图片的地址保存起来，在加载图片的时候将生成的bitmap对象用图片地址的字符串保存在map里，不用的时候再根据key值回收。

下面是实现的几个主要部分

1、工具类

public class ImageManager {

static int index = 0;

    public static ConcurrentHashMap<String, Bitmap> imageMap = new ConcurrentHashMap<String, Bitmap>();

    public static String ISFALSE="ISFALSE";

    public static String ISTRUE="ISTRUE";

    public static List<String[]> getSD(String dir) {

        List<String[]> it = new ArrayList<String[]>();

        File f = new File(dir);

        File[] files = f.listFiles();

        if (files != null) {

            for (int i = 0; i < files.length; i++) {

                String[] s = new String[2];

                File file = files[i];

 

                if (file.isFile()) {

                    if (getImageFile(file.getPath())) {

                        System.out.println("file   " + String.valueOf(file));

                        s[0] = file.getPath();

                        s[1] = file.getName();

                        it.add(s);

                    }

                } else if(file.isDirectory()){

                    System.out.println("file.isDirectory()   " + file.getAbsolutePath());

                    getSD(String.valueOf(file.getAbsolutePath()));

                }

            }

        }

        return it;

    }

    public static boolean getImageFile(String fName) {

        boolean re;

        String end = fName

                .substring(fName.lastIndexOf(".") + 1, fName.length())

                .toLowerCase();

        if (end.equals("jpg") || end.equals("gif") || end.equals("png")

                || end.equals("jpeg") || end.equals("bmp")) {

            re = true;

        } else {

            re = false;

        }

        return re;

    }

    public static Bitmap getImage(String fileName) {

        try {

            File file = new File(fileName);

            Bitmap bitmap = null;

            bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());

            addImage(fileName, bitmap);

            return bitmap;

        } catch (Exception e) {

            return null;

        }

    }

    public static Bitmap getRefImage(String fileName) {

        try {

            File file = new File(fileName);

            Bitmap bitmap = null;

            bitmap = BitmapFactory.decodeFile(file.getAbsolutePath());

            addImage(fileName, bitmap);

            return createReflectionImageWithOrigin(fileName, bitmap);

        } catch (Exception e) {

            return null;

        }

    }

    public static void addImage(String uri, Bitmap bitmap) {

        imageMap.put(uri.toString(), bitmap);

    }

    private static void clearBitmap(String uri) {

        if (imageMap.get(uri) != null) {

            System.out.println("remove image:" + uri);

            imageMap.get(uri).recycle();

            imageMap.remove(uri);

        }

    }

    // 清空左边到0、右边到最后，保留中间

    public static List<ImageMessage> clearImage(List<ImageMessage> imageList,

            int start, int end) {

        if (start >= 0 && end < imageList.size()) {

            for (int i = 0; i < start; i++) {

                if (imageList.get(i).getIsNull().equals(ISFALSE)) {

                    imageList.get(i).setIsNull(ISTRUE);

                    clearBitmap(imageList.get(i).getPath().toString());

                    clearBitmap(imageList.get(i).getPath().toString() + "1");

                    clearBitmap(imageList.get(i).getPath().toString() + "2");

                    imageList.get(i).setImage(null);

                }

            }

            for (int i = end + 1; i < imageList.size(); i++) {

                if (imageList.get(i).getIsNull().equals(ISFALSE)) {

                    imageList.get(i).setIsNull(ISTRUE);

                    clearBitmap(imageList.get(i).getPath().toString());

                    clearBitmap(imageList.get(i).getPath().toString() + "1");

                    clearBitmap(imageList.get(i).getPath().toString() + "2");

                    imageList.get(i).setImage(null);

                }

            }

        }

        return imageList;

    }

    // 获得带倒影的图片方法

    public static Bitmap createReflectionImageWithOrigin(String str,

            Bitmap bitmap) {

        final int reflectionGap = 0;//原图片与倒影图片之间的缝隙

        int width = bitmap.getWidth();

        int height = bitmap.getHeight();

        Matrix matrix = new Matrix();

        matrix.preScale(1, -1);

        Bitmap reflectionImage = Bitmap.createBitmap(bitmap, 0, height / 2,

                width, height / 2, matrix, false);

        addImage(str + "1", reflectionImage);

        Bitmap bitmapWithReflection = Bitmap.createBitmap(width,

                (height + height / 2), Config.ARGB_8888);

        addImage(str + "2", bitmapWithReflection);

        Canvas canvas = new Canvas(bitmapWithReflection);

        canvas.drawBitmap(bitmap, 0, 0, null);

        Paint deafalutPaint = new Paint();

        canvas.drawRect(0, height, width, height + reflectionGap, deafalutPaint);

        canvas.drawBitmap(reflectionImage, 0, height + reflectionGap, null);

  

评论

4 楼 Mr.Cheney 2012-09-17  

代码太乱了

3 楼 heguikun 2011-11-25  

这个想法跟我的一样，我困扰好几天，实在没办法了，好像也没有更好的办法了，这样做我觉得是唯一的办法，楼主英明，500长图片啊，不这样做 没有其他可言了

2 楼 muyu114 2011-09-26  

你这个方法不错，但是代码怎么有点乱啊，能给个完整的么[e-mail]

1 楼 ckarying 2011-07-09  

你好，这份代码能不能给我发一个demo，我有急用，谢谢了，我的email是[e-mail]