android中常用的图片处理方法，涉及uri位图等多种图片转换

直接上代码，代码中有方法的主要作用

/**
 * Created by sunshaobei on 2017/3/15.
 */

public class OwnUtil {
    public static String compressImage(String filePath, String targetPath, int quality) {
        Bitmap bm = getSmallBitmap(filePath);//获取一定尺寸的图片
        File outputFile = new File(targetPath);
        try {
            if (!outputFile.exists()) {
                outputFile.getParentFile().mkdirs();
                //outputFile.createNewFile();
            } else {
                outputFile.delete();
            }
            FileOutputStream out = new FileOutputStream(outputFile);
            bm.compress(Bitmap.CompressFormat.JPEG, quality, out);
        } catch (Exception e) {
        }
        return outputFile.getPath();
    }

    /**
     * 根据路径获得图片信息并按比例压缩，返回bitmap
     */
    public static Bitmap getSmallBitmap(String filePath) {
        final BitmapFactory.Options options = new BitmapFactory.Options();
        options.inJustDecodeBounds = true;//只解析图片边沿，获取宽高
        BitmapFactory.decodeFile(filePath, options);
        // 计算缩放比
        options.inSampleSize = calculateInSampleSize(options, 480, 800);
        // 完整解析图片返回bitmap
        options.inJustDecodeBounds = false;
        return BitmapFactory.decodeFile(filePath, options);
    }

    public static int calculateInSampleSize(BitmapFactory.Options options,
                                            int reqWidth, int reqHeight) {
        final int height = options.outHeight;
        final int width = options.outWidth;
        int inSampleSize = 1;
        if (height > reqHeight || width > reqWidth) {
            final int heightRatio = Math.round((float) height / (float) reqHeight);
            final int widthRatio = Math.round((float) width / (float) reqWidth);
            inSampleSize = heightRatio < widthRatio ? heightRatio : widthRatio;
        }
        return inSampleSize;
    }

    /**
     * 从uri中获取bitmap
     *
     * @param uri
     * @return
     */
    public static String getRealPathFromURI(Activity activity, Uri uri) {
        String[] proj = {
                MediaStore.Video.Media.DISPLAY_NAME,
                MediaStore.Video.Media.SIZE,
                MediaStore.Images.Media.DATA,//绝对路径
                MediaStore.Video.Media.MIME_TYPE
        };
        Cursor cursor = activity.getContentResolver().query(uri, proj, null, null, null);
        int audioColumnIndex = cursor.getColumnIndexOrThrow(MediaStore.Audio.Media.DATA);
        cursor.moveToFirst();
        String path = cursor.getString(audioColumnIndex);
        return path;
    }

    /**
     * 将本地资源转换成bitmap
     *
     * @param filePath
     * @return
     */
    public static Bitmap getVideoThumbnail(String filePath) {
        Bitmap bitmap = null;
        MediaMetadataRetriever retriever = new MediaMetadataRetriever();
        try {
            retriever.setDataSource(filePath);
            bitmap = retriever.getFrameAtTime();
        } catch (IllegalArgumentException e) {
            e.printStackTrace();
        } catch (RuntimeException e) {
            e.printStackTrace();
        } finally {
            try {
                retriever.release();
            } catch (RuntimeException e) {
                e.printStackTrace();
            }
        }
        return bitmap;
    }


    public static String saveBitmapFile(Bitmap bitmap) {
        String path = Environment.getExternalStorageDirectory().getAbsolutePath() + "/Papaqun/image.jpg";
        File file = new File(path);//将要保存图片的路径
        BufferedOutputStream bos = null;
        try {
            bos = new BufferedOutputStream(new FileOutputStream(file));
            bitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);
            bos.flush();
            bos.close();
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            if (bos != null) {
                try {
                    bos.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
        return path;
    }

    @SuppressLint("NewApi")
    public static String getPathByUri4kitkat(final Context context, final Uri uri) {
        final boolean isKitKat = Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT;
        // DocumentProvider
        if (isKitKat && DocumentsContract.isDocumentUri(context, uri)) {
            if (isExternalStorageDocument(uri)) {// ExternalStorageProvider
                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];
                }
            } else if (isDownloadsDocument(uri)) {// DownloadsProvider
                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);
            } else if (isMediaDocument(uri)) {// MediaProvider
                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);
            }
        } else if ("content".equalsIgnoreCase(uri.getScheme())) {// MediaStore
            // (and
            // general)
            return getDataColumn(context, uri, null, null);
        } else if ("file".equalsIgnoreCase(uri.getScheme())) {// File
            return uri.getPath();
        }
        return null;
    }

    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 column_index = cursor.getColumnIndexOrThrow(column);
                return cursor.getString(column_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());
    }
}

有用的请直接copy