遇到问题：有的手机拍摄的图片自动旋转90度，有的图片旋转了180度，有的手机是正常的，导致显示到界面的上的头像不准确。服务器要求的是正的，这样问题就来了，不能用户发个照片在微博上看到的是被旋转了的啊，另外一个项目里旋转了的图片直接匹配出现问题，这个更严重。
解决思路：
1.拿到照相机自带的返回的uri；
2.根据uri获取到照片在手机上的绝对路径，根据路径获取获取照片的旋转角度（此处应该特别注意：一定要是照相机返回的原始的uri,不然获取到的旋转角度始终为0）；
3.根据uri获取到bitmap
4.根据动态获取到旋转角度来旋转图片
5.把图片设置到view上或传到服务器
直接上代码：
1.根据uri获取到照片在手机上的绝对路径，根据路径获取获取照片的旋转角度（此处应该特别注意：一定要是照相机返回的原始的uri,不然获取到的旋转角度始终为0）；
/**
* 专为Android4.4及以上设计的从Uri获取文件绝对路径，以前的方法已不好使
*/
@SuppressLint("NewApi")
public static String getPath(final Context context, final 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];
}
// TODO handle non-primary volumes
}
// 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 getDataColumn(context, uri, null, null);
}
// File
else if ("file".equalsIgnoreCase(uri.getScheme())) {
return uri.getPath();
}
return null;
}
/**
* Get the value of the data column for this Uri. This is useful for
* MediaStore Uris, and other file-based ContentProviders.
*
* @param context The context.
* @param uri The Uri to query.
* @param selection (Optional) Filter used in the query.
* @param selectionArgs (Optional) Selection arguments used in the query.
* @return The value of the _data column, which is typically a file path.
*/
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());
}
2.根据图片的绝对路径获取默认的角度：
/**
* 读取图片的旋转的角度
*
* @param path 图片绝对路径
* @return 图片的旋转角度
*/
public static int getBitmapDegree(String path) {
int degree = 0;
try {
// 从指定路径下读取图片，并获取其EXIF信息
ExifInterface exifInterface = new ExifInterface(path);
// 获取图片的旋转信息
int orientation = exifInterface.getAttributeInt(ExifInterface.TAG_ORIENTATION,
ExifInterface.ORIENTATION_NORMAL);
switch (orientation) {
case ExifInterface.ORIENTATION_ROTATE_90:
degree = 90;
break;
case ExifInterface.ORIENTATION_ROTATE_180:
degree = 180;
break;
case ExifInterface.ORIENTATION_ROTATE_270:
degree = 270;
break;
}
} catch (IOException e) {
e.printStackTrace();
}
return degree;
}
3.根据uri获取到bitmap
public static Bitmap getBitmapFromUri(Context mContext, Uri uri) {
try {
// 读取uri所在的图片
Bitmap bitmap = MediaStore.Images.Media.getBitmap(mContext.getContentResolver(), uri);
return bitmap;
} catch (Exception e) {
e.printStackTrace();
return null;
}
}
- 根据动态获取到旋转角度来旋转图片返回bitmap
/**
* 旋转图片，使图片保持正确的方向。
*
* @param bitmap 原始图片
* @param degrees 原始图片的角度
* @return Bitmap 旋转后的图片
*/
public static Bitmap rotateBitmap(Bitmap bitmap, int degrees) {
if (degrees == 0 || null == bitmap) {
return bitmap;
}
Matrix matrix = new Matrix();
matrix.setRotate(degrees, bitmap.getWidth() / 2, bitmap.getHeight() / 2);
Bitmap bmp = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);
bitmap.recycle();
return bmp;
}
项目中可以把以上的方法统一放到一个工具类中方便管理
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