从路径uri加载Bitmap,缩小图片到指定大小的方法记录

来源：互联网发布：11年总决赛数据编辑：程序博客网时间：2024/05/16 12:55

根据uri获取实际的文件路径,位于工具类  @TargetApi(Build.VERSION_CODES.KITKAT)    public static String getRealPathFromURI(Uri uri) {        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;        // DocumentProvider        if (isKitKat && DocumentsContract.isDocumentUri(context_, uri)) {            // ExternalStorageProvider            if (isExternalStorageDocument(uri)) {                final String docId = DocumentsContract.getDocumentId(uri);                final String[] split = docId.split(":");                final String type = split[0];//                if ("primary".equalsIgnoreCase(type)) {                return Environment.getExternalStorageDirectory() + "/" + split[1];//                }            }            // DownloadsProvider            else if (isDownloadsDocument(uri)) {                final String id = DocumentsContract.getDocumentId(uri);                final Uri contentUri = ContentUris.withAppendedId(                        Uri.parse("content://downloads/public_downloads"), Long.valueOf(id));                return getDataColumn(context_, contentUri, null, null);            }            // MediaProvider            else if (isMediaDocument(uri)) {                final String docId = DocumentsContract.getDocumentId(uri);                final String[] split = docId.split(":");                final String type = split[0];                Uri contentUri = null;                if ("image".equals(type)) {                    contentUri = MediaStore.Images.Media.EXTERNAL_CONTENT_URI;                } else if ("video".equals(type)) {                    contentUri = MediaStore.Video.Media.EXTERNAL_CONTENT_URI;                } else if ("audio".equals(type)) {                    contentUri = MediaStore.Audio.Media.EXTERNAL_CONTENT_URI;                }                final String selection = "_id=?";                final String[] selectionArgs = new String[]{split[1]};                return getDataColumn(context_, contentUri, selection, selectionArgs);            }        }        // MediaStore (and general)        else if ("content".equalsIgnoreCase(uri.getScheme())) {            // Return the remote address            if (isGooglePhotosUri(uri))                return uri.getLastPathSegment();            return getDataColumn(context_, uri, null, null);        }        // File        else if ("file".equalsIgnoreCase(uri.getScheme())) {            return uri.getPath();        }        return "";    }    public static String getDataColumn(Context context, Uri uri, String selection,                                       String[] selectionArgs) {        Cursor cursor = null;        final String column = "_data";        final String[] projection = {column};        try {            cursor = context.getContentResolver().query(uri, projection, selection, selectionArgs,                    null);            if (cursor != null && cursor.moveToFirst()) {                final int index = cursor.getColumnIndexOrThrow(column);                return cursor.getString(index);            }        } finally {            if (cursor != null)                cursor.close();        }        return null;    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is ExternalStorageProvider.     */    public static boolean isExternalStorageDocument(Uri uri) {        return "com.android.externalstorage.documents".equals(uri.getAuthority());    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is DownloadsProvider.     */    public static boolean isDownloadsDocument(Uri uri) {        return "com.android.providers.downloads.documents".equals(uri.getAuthority());    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is MediaProvider.     */    public static boolean isMediaDocument(Uri uri) {        return "com.android.providers.media.documents".equals(uri.getAuthority());    }    /**     * @param uri The Uri to check.     * @return Whether the Uri authority is Google Photos.     */    public static boolean isGooglePhotosUri(Uri uri) {        return "com.google.android.apps.photos.content".equals(uri.getAuthority());    }

加载时第一次缩放主要是为了缩小图片,节约加载内存  public Bitmap resizeImage1(String path,int dstWidth, int dstHeight) {        BitmapFactory.Options options = new BitmapFactory.Options();        options.inJustDecodeBounds = true;//不加载bitmap到内存中        BitmapFactory.decodeFile(path, options);        int srcWidth = options.outWidth;        int srcHeight = options.outHeight;        options.inDither = false;        options.inPreferredConfig = Bitmap.Config.RGB_565;        options.inSampleSize = 1;        int inSampleSize = 1;        if (srcWidth != 0 && srcHeight != 0 && dstWidth != 0 && dstHeight != 0) {            if (srcHeight > dstHeight || srcWidth > dstWidth) {                if (srcWidth > srcHeight) {                    inSampleSize = Math.round((float) srcHeight / (float) dstHeight);                } else {                    inSampleSize = Math.round((float) srcWidth / (float) dstWidth);                }            }//            inSampleSize的值只有为2的指数幂时才有效如1,2,4,6,这里宁愿多压缩一点节约内存所以加3            options.inSampleSize = inSampleSize + 3;            L.d("bitmap:111sampleSize =%s ,srcWidth=%s,srcHeight=%s,dstWidth=%s,dstHeight=%s", options.inSampleSize, srcWidth, srcHeight, dstWidth, dstHeight);        }        options.inJustDecodeBounds = false;        return BitmapFactory.decodeFile(path, options);    }

第二次缩放,把图片尺寸缩放到指定大小 public Bitmap resizeImage2(Bitmap bitmap, int w, int h)    {        Bitmap BitmapOrg = bitmap;        int width = BitmapOrg.getWidth();        int height = BitmapOrg.getHeight();        int newWidth = w;        int newHeight = h;        float scaleWidth = ((float) newWidth) / width;        float scaleHeight = ((float) newHeight) / height;        Matrix matrix = new Matrix();        matrix.postScale(scaleWidth, scaleHeight);        // if you want to rotate the Bitmap        // matrix.postRotate(45);        Bitmap resizedBitmap = Bitmap.createBitmap(BitmapOrg, 0, 0, width,                height, matrix, true);        return resizedBitmap;    }

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