Android(安卓)Uri，Path与File、Bitmap的相互转换（新）

Android Uri，Path与File的相互转换（新）

一、path->file

File file = new File(path);

二、 file->path

String path = file.getPath();

注意URI和Uri的区别

1 URI：是java.net的子类
2 Uri ：是android.net的子类，Uri 不能被实例化

三、 URI->File

File file = null;   //图片地址        try {            file = new File(new URI(uri.toString()));        } catch (URISyntaxException e) {            e.printStackTrace();        }

四、 File->URI

URI uri = file.toURI();

五、 Path->Uri

Uri uri = Uri.parse(path);

六、Uri->Path
网上很多通过context.getContentResolver().query方式可能会遇到空指针的问题
这里通过使用：https://juejin.im/entry/5a508655f265da3e2d3340d5
提供的封装方法去处理Uri转Path的问题

传入 context 和 Uri即可

public class UriTofilePath {    public static String getFilePathByUri(Context context, Uri uri) {        String path = null;        // 4.4及之后的 是以 content:// 开头的，比如 content://com.android.providers.media.documents/document/image%3A235700        if (ContentResolver.SCHEME_CONTENT.equals(uri.getScheme()) && Build.VERSION.SDK_INT >= Build.VERSION_CODES.KITKAT) {            if (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)) {                        path = Environment.getExternalStorageDirectory() + "/" + split[1];                        return path;                    }                } 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));                    path = getDataColumn(context, contentUri, null, null);                    return path;                } 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]};                    path = getDataColumn(context, contentUri, selection, selectionArgs);                    return path;                }            }        }else {            // 以 file:// 开头的            if (ContentResolver.SCHEME_FILE.equals(uri.getScheme())) {                path = uri.getPath();                return path;            }            // 以 content:// 开头的，比如 content://media/extenral/images/media/17766            if (ContentResolver.SCHEME_CONTENT.equals(uri.getScheme()) && Build.VERSION.SDK_INT < Build.VERSION_CODES.KITKAT) {                Cursor cursor = context.getContentResolver().query(uri, new String[]{MediaStore.Images.Media.DATA}, null, null, null);                if (cursor != null) {                    if (cursor.moveToFirst()) {                        int columnIndex = cursor.getColumnIndexOrThrow(MediaStore.Images.Media.DATA);                        if (columnIndex > -1) {                            path = cursor.getString(columnIndex);                        }                    }                    cursor.close();                }                return path;            }        }        return null;    }    private 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;    }    private static boolean isExternalStorageDocument(Uri uri) {        return "com.android.externalstorage.documents".equals(uri.getAuthority());    }    private static boolean isDownloadsDocument(Uri uri) {        return "com.android.providers.downloads.documents".equals(uri.getAuthority());    }    private static boolean isMediaDocument(Uri uri) {        return "com.android.providers.media.documents".equals(uri.getAuthority());    }}

**七、 Uri->file **
可以先Uri->path 再path->file

八、file->Uri
可以先 file->path 再path->Uri

九、删除Uri

MainActivity.this.getContentResolver().delete(imageUri, null, null);

图片的Uri转Bitmap

Bitmap bitmap = BitmapFactory.decodeStream(contentResolver.openInputStream(xxxUri))

bitmap转为jpg文件

BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(file));bitmap.compress(Bitmap.CompressFormat.JPEG, 100, bos);

资源文件转Bitmap

BitmapFactory.decodeResource(getResources(),R.drawable.ic );

jpg或者png文件转Bitmap

String fileName = "/data/com.test/aa.png;  Bitmap bm = BitmapFactory.decodeFile(fileName);

Android Uri，Path与File的相互转换（新）

注意URI和Uri的区别

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