我正在做一个应用程序将图像从图库保存到ImageView,为此我必须保存在sharedPreference中,当我离开应用程序并返回时,图像仍然存在。
ps:我已经在这里读过一个问题,但是对我来说并不适用
有人可以帮助我吗?请
JAVA文件的一部分
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protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
sharedPreferences = getSharedPreferences("data", context.MODE_PRIVATE);
imgButton = (ImageView) findViewById(R.id.AddPic);
imgButton.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
Intent GaleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(GaleryIntent, RESULT_LOAD_IMAGE);
}
});
}
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == RESULT_LOAD_IMAGE && resultCode == RESULT_OK && null != data) {
SelectedImage = data.getData();
performCrop();
}
else if(requestCode == PIC_CROP){
Bundle extras = data.getExtras();
//get the cropped bitmap
Bitmap thePic = extras.getParcelable("data");
ByteArrayOutputStream baos = new ByteArrayOutputStream();
thePic.compress(Bitmap.CompressFormat.PNG, 100, baos); //bm is the bitmap object
byte[] byteArray = baos.toByteArray();
String imageString= Base64.encodeToString(byteArray , Base64.DEFAULT);
byte[] imageBytes = Base64.decode(imageString.getBytes());
imgButton.setImageBitmap(BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length));
}
}
private void performCrop() {
try {
Intent cropIntent = new Intent("com.android.camera.action.CROP");
cropIntent.setDataAndType(SelectedImage, "image/*");
cropIntent.putExtra("crop", "true");
cropIntent.putExtra("aspectX", 1);
cropIntent.putExtra("aspectY", 1);
cropIntent.putExtra("outputX", 256);
cropIntent.putExtra("outputY", 256);
cropIntent.putExtra("return-data", true);
startActivityForResult(cropIntent, PIC_CROP);
}
catch(ActivityNotFoundException anfe){
String errorMessage = "Whoops - your device doesn't support the crop action!";
Toast toast = Toast.makeText(this, errorMessage, Toast.LENGTH_SHORT);
toast.show();
}
}}
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我试过这个,第一个答案:How to save cropped image uri in shared Preference 但没有工作
也许我必须将位图转换为字符串或做其他事情,但我不知道
无论如何,无论如何答案 0 :(得分:0)
您可以在SharedPreference中保存裁剪的图像位图。因为我们只能在SharedPreference中存储Boolean,Float,Int,Long,String值。但是你可以做的一件事就是将Bitmap转换为Base64 String并保存在SharedPreference中,然后在用户打开应用程序时检索字符串..
将位图转换为字节数组,如下所示:
ByteArrayOutputStream baos = new ByteArrayOutputStream();
thePic.compress(Bitmap.CompressFormat.PNG, 100, baos); //bm is the bitmap object
byte[] byteArray = baos.toByteArray();
从像这样的字节数组中获取String
String imageString= Base64.encodeToString(byteArray , Base64.DEFAULT);
现在将此String保存在SharedPreference中,当您想要显示图像时,只需从SharedPreference获取此String并在ImageView中显示如下
byte[] imageBytes = Base64.decode(imageString.getBytes());
imageView.setImageBitmap(BitmapFactory.decodeByteArray(imageBytes, 0, imageBytes.length));
答案 1 :(得分:0)
import android.annotation.TargetApi;
import android.content.ContentUris;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Build;
import android.os.Environment;
import android.provider.DocumentsContract;
import android.provider.MediaStore;
public class FetchPath {
/**
* Get a file path from a Uri. This will get the the path for Storage Access
* Framework Documents, as well as the _data field for the MediaStore and
* other file-based ContentProviders.
*
* @param context The context.
* @param uri The Uri to query.
* @author paulburke
*/
@TargetApi(Build.VERSION_CODES.KITKAT)
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 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 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 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());
}
}
用法
Uri photoUri = data.getData();
if (photoUri != null) {
String filePath = FetchPath.getPath(this, photoUri);
}