如何从我的应用程序的库（SD卡）中选择图像？-Java 学习之路

334

这个问题最初是针对Android 1.6提出的 .

我在我的应用程序中处理照片选项 .

我的Activity中有一个按钮和一个ImageView . 当我点击按钮时，它会重定向到图库，我可以选择一个图像 . 选定的图像将出现在我的ImageView中 .

10 回答

11
近5年后更新的答案：

原始答案中的代码不再可靠地工作，因为来自各种来源的图像有时会返回不同的内容URI，即 content:// 而不是 file:// . 更好的解决方案是简单地使用 context.getContentResolver().openInputStream(intent.getData()) ，因为它将返回一个您可以根据需要处理的InputStream .

例如， BitmapFactory.decodeStream() 在这种情况下可以正常工作，因为您还可以使用Options和inSampleSize字段对大图像进行缩减采样并避免内存问题 .

但是，像Google Cloud 端硬盘这样的内容会将URI返回到尚未实际下载的图片 . 因此，您需要在后台线程上执行getContentResolver（）代码 .

原始答案：

其他答案解释了如何发送意图，但他们没有很好地解释如何处理响应 . 以下是有关如何执行此操作的示例代码：
```
protected void onActivityResult(int requestCode, int resultCode, 
       Intent imageReturnedIntent) {
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent); 

    switch(requestCode) { 
    case REQ_CODE_PICK_IMAGE:
        if(resultCode == RESULT_OK){  
            Uri selectedImage = imageReturnedIntent.getData();
            String[] filePathColumn = {MediaStore.Images.Media.DATA};

            Cursor cursor = getContentResolver().query(
                               selectedImage, filePathColumn, null, null, null);
            cursor.moveToFirst();

            int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
            String filePath = cursor.getString(columnIndex);
            cursor.close();


            Bitmap yourSelectedImage = BitmapFactory.decodeFile(filePath);
        }
    }
}
```
在此之后，您已经将选定的图像存储在“yourSelectedImage”中，以执行您想要的任何操作 . 此代码通过在ContentResolver数据库中获取映像的位置来工作，但这本身是不够的 . 每个图像有大约18列信息，从其文件路径到“最后修改日期”到拍摄照片的GPS坐标，尽管实际上没有使用许多字段 .

为了节省时间，在您使用 columnIndex 代码之前，不要知道它所在的列 . 这只是根据其名称获取列的编号，与过滤过程中使用的相同 . 一旦你最终能够使用我给出的最后一行代码将图像解码为位图 .
回复于 2024-05-17T10:48:18+08:00

private static final int SELECT_PHOTO = 100;

开始意图

Intent photoPickerIntent = new Intent(Intent.ACTION_PICK);
photoPickerIntent.setType("image/*");
startActivityForResult(photoPickerIntent, SELECT_PHOTO);

处理结果

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) { 
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent); 

    switch(requestCode) { 
    case SELECT_PHOTO:
        if(resultCode == RESULT_OK){  
            Uri selectedImage = imageReturnedIntent.getData();
            InputStream imageStream = getContentResolver().openInputStream(selectedImage);
            Bitmap yourSelectedImage = BitmapFactory.decodeStream(imageStream);
        }
    }
}

或者，您也可以对图像进行下采样以避免OutOfMemory错误 .

private Bitmap decodeUri(Uri selectedImage) throws FileNotFoundException {

        // Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o);

        // The new size we want to scale to
        final int REQUIRED_SIZE = 140;

        // Find the correct scale value. It should be the power of 2.
        int width_tmp = o.outWidth, height_tmp = o.outHeight;
        int scale = 1;
        while (true) {
            if (width_tmp / 2 < REQUIRED_SIZE
               || height_tmp / 2 < REQUIRED_SIZE) {
                break;
            }
            width_tmp /= 2;
            height_tmp /= 2;
            scale *= 2;
        }

        // Decode with inSampleSize
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        return BitmapFactory.decodeStream(getContentResolver().openInputStream(selectedImage), null, o2);

    }

回复于 2024-05-17T10:48:18+08:00

14
您必须为结果启动图库意图 .
```
Intent i = new Intent(Intent.ACTION_PICK,
               android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(i, ACTIVITY_SELECT_IMAGE);
```
然后在 onActivityForResult 中，调用 intent.getData() 以获取图像的Uri . 然后，您需要从ContentProvider获取图像 .
回复于 2024-05-17T10:48:18+08:00

415

这是一个经过测试的图像和视频代码 . 它适用于所有小于19且大于19的API .

图片：

if (Build.VERSION.SDK_INT <= 19) {
                        Intent i = new Intent();
                        i.setType("image/*");
                        i.setAction(Intent.ACTION_GET_CONTENT);
                        i.addCategory(Intent.CATEGORY_OPENABLE);
                        startActivityForResult(i, 10);
                    } else if (Build.VERSION.SDK_INT > 19) {
                        Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                        startActivityForResult(intent, 10);
                    }

视频：

if (Build.VERSION.SDK_INT <= 19) {
                        Intent i = new Intent();
                        i.setType("video/*");
                        i.setAction(Intent.ACTION_GET_CONTENT);
                        i.addCategory(Intent.CATEGORY_OPENABLE);
                        startActivityForResult(i, 20);
                    } else if (Build.VERSION.SDK_INT > 19) {
                        Intent intent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Video.Media.EXTERNAL_CONTENT_URI);
                        startActivityForResult(intent, 20);
                    }

@Override
        public void onActivityResult(int requestCode, int resultCode, Intent data) {
            super.onActivityResult(requestCode, resultCode, data);
            if (resultCode == Activity.RESULT_OK) {

                if (requestCode == 10) {
                    Uri selectedImageUri = data.getData();
                    String selectedImagePath = getRealPathFromURI(selectedImageUri);
                } else if (requestCode == 20) {
                    Uri selectedVideoUri = data.getData();
                    String selectedVideoPath = getRealPathFromURI(selectedVideoUri);
                }
    }
}
         public String getRealPathFromURI(Uri uri) {
                if (uri == null) {
                    return null;
                }
                String[] projection = {MediaStore.Images.Media.DATA};
                Cursor cursor = getActivity().getContentResolver().query(uri, projection, null, null, null);
                if (cursor != null) {
                    int column_index = cursor
                            .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
                    cursor.moveToFirst();
                    return cursor.getString(column_index);
                }
                return uri.getPath();
            }

回复于 2024-05-17T10:48:18+08:00

8
这样做是为了启动图库并允许用户选择图像：
```
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.setType("image/*");
startActivityForResult(intent, IMAGE_PICK);
```
然后在 onActivityResult() 中使用返回的图像的URI来设置ImageView上的图像 .
回复于 2024-05-17T10:48:18+08:00

public class EMView extends Activity {
ImageView img,img1;
int column_index;
  Intent intent=null;
// Declare our Views, so we can access them later
String logo,imagePath,Logo;
Cursor cursor;
//YOU CAN EDIT THIS TO WHATEVER YOU WANT
private static final int SELECT_PICTURE = 1;

 String selectedImagePath;
//ADDED
 String filemanagerstring;

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);
    img= (ImageView)findViewById(R.id.gimg1);



    ((Button) findViewById(R.id.Button01))
    .setOnClickListener(new OnClickListener() {

        public void onClick(View arg0) {

            // in onCreate or any event where your want the user to
            // select a file
            Intent intent = new Intent();
            intent.setType("image/*");
            intent.setAction(Intent.ACTION_GET_CONTENT);
            startActivityForResult(Intent.createChooser(intent,
                    "Select Picture"), SELECT_PICTURE);


        }
    });
}

//UPDATED
@Override
public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == Activity.RESULT_OK) {
        if (requestCode == SELECT_PICTURE) {
            Uri selectedImageUri = data.getData();

            //OI FILE Manager
            filemanagerstring = selectedImageUri.getPath();

            //MEDIA GALLERY
            selectedImagePath = getPath(selectedImageUri);


            img.setImageURI(selectedImageUri);

           imagePath.getBytes();
           TextView txt = (TextView)findViewById(R.id.title);
           txt.setText(imagePath.toString());


           Bitmap bm = BitmapFactory.decodeFile(imagePath);

          // img1.setImageBitmap(bm);



        }

    }

}

//UPDATED!
public String getPath(Uri uri) {
String[] projection = { MediaColumns.DATA };
Cursor cursor = managedQuery(uri, projection, null, null, null);
column_index = cursor
        .getColumnIndexOrThrow(MediaColumns.DATA);
cursor.moveToFirst();
 imagePath = cursor.getString(column_index);

return cursor.getString(column_index);
}

}

回复于 2024-05-17T10:48:18+08:00

public class BrowsePictureActivity extends Activity {
private static final int SELECT_PICTURE = 1;

private String selectedImagePath;

public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.main);

    ((Button) findViewById(R.id.Button01))
            .setOnClickListener(new OnClickListener() {

                public void onClick(View arg0) {

                    Intent intent = new Intent();
                    intent.setType("image/*");
                    intent.setAction(Intent.ACTION_GET_CONTENT);
                    startActivityForResult(Intent.createChooser(intent,
                            "Select Picture"), SELECT_PICTURE);
                }
            });
}

public void onActivityResult(int requestCode, int resultCode, Intent data) {
    if (resultCode == RESULT_OK) {
        if (requestCode == SELECT_PICTURE) {
            Uri selectedImageUri = data.getData();
            selectedImagePath = getPath(selectedImageUri);
        }
    }
}

public String getPath(Uri uri) {

        if( uri == null ) {
            return null;
        }

        // this will only work for images selected from gallery
        String[] projection = { MediaStore.Images.Media.DATA };
        Cursor cursor = managedQuery(uri, projection, null, null, null);
        if( cursor != null ){
            int column_index = cursor
            .getColumnIndexOrThrow(MediaStore.Images.Media.DATA);
            cursor.moveToFirst();
            return cursor.getString(column_index);
        }

        return uri.getPath();
}

}

回复于 2024-05-17T10:48:18+08:00

314
由于某些原因，该线程中的所有答案都在 onActivityResult() 中尝试对收到的 Uri 进行后处理，就像获取图像的真实路径一样，然后使用 BitmapFactory.decodeFile(path) 来获取 Bitmap .

这一步是不必要的 . ImageView 类有一个名为 setImageURI(uri) 的方法 . 把你的uri传递给它，你应该完成 .
```
Uri imageUri = data.getData();
imageView.setImageURI(imageUri);
```
有关完整的工作示例，您可以在这里查看：http://androidbitmaps.blogspot.com/2015/04/loading-images-in-android-part-iii-pick.html

PS：
在要加载的图像太大而无法放入内存的情况下，将 Bitmap 放在单独的变量中是有意义的，并且需要按比例缩小操作来防止 OurOfMemoryError ，如@siamii答案中所示 .
回复于 2024-05-17T10:48:18+08:00

调用chooseImage方法，如 -

public void chooseImage(ImageView v)
{
    Intent intent = new Intent(Intent.ACTION_PICK);
    intent.setType("image/*");
    startActivityForResult(intent, SELECT_PHOTO);
}

@Override
protected void onActivityResult(int requestCode, int resultCode, Intent imageReturnedIntent) {
    // TODO Auto-generated method stub
    super.onActivityResult(requestCode, resultCode, imageReturnedIntent);

    if(imageReturnedIntent != null)
    {
        Uri selectedImage = imageReturnedIntent.getData();
    switch(requestCode) { 
    case SELECT_PHOTO:
        if(resultCode == RESULT_OK)
        {
            Bitmap datifoto = null;
            temp.setImageBitmap(null);
            Uri picUri = null;
            picUri = imageReturnedIntent.getData();//<- get Uri here from data intent
             if(picUri !=null){
               try {
                   datifoto = android.provider.MediaStore.Images.Media.getBitmap(this.getContentResolver(),                                 picUri);
                   temp.setImageBitmap(datifoto);
               } catch (FileNotFoundException e) {
                  throw new RuntimeException(e);
               } catch (IOException e) {
                  throw new RuntimeException(e);
               } catch (OutOfMemoryError e) {
                Toast.makeText(getBaseContext(), "Image is too large. choose other", Toast.LENGTH_LONG).show();
            }

        }
        }
        break;

}
    }
    else
    {
        //Toast.makeText(getBaseContext(), "data null", Toast.LENGTH_SHORT).show();
    }
}

回复于 2024-05-17T10:48:18+08:00

#initialize in main activity 
    path = Environment.getExternalStorageDirectory()
            + "/images/make_machine_example.jpg"; #
     ImageView image=(ImageView)findViewById(R.id.image);
 //--------------------------------------------------||

 public void FromCamera(View) {

    Log.i("camera", "startCameraActivity()");
    File file = new File(path);
    Uri outputFileUri = Uri.fromFile(file);
    Intent intent = new Intent(
            android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
    intent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
    startActivityForResult(intent, 1);

}

public void FromCard() {
    Intent i = new Intent(Intent.ACTION_PICK,
            android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
    startActivityForResult(i, 2);
}

 protected void onActivityResult(int requestCode, int resultCode, Intent data) {

    super.onActivityResult(requestCode, resultCode, data);

    if (requestCode == 2 && resultCode == RESULT_OK
            && null != data) {

        Uri selectedImage = data.getData();
        String[] filePathColumn = { MediaStore.Images.Media.DATA };

        Cursor cursor = getContentResolver().query(selectedImage,
                filePathColumn, null, null, null);
        cursor.moveToFirst();

        int columnIndex = cursor.getColumnIndex(filePathColumn[0]);
        String picturePath = cursor.getString(columnIndex);
        cursor.close();

        bitmap = BitmapFactory.decodeFile(picturePath);
        image.setImageBitmap(bitmap);

        if (bitmap != null) {
            ImageView rotate = (ImageView) findViewById(R.id.rotate);

        }

    } else {

        Log.i("SonaSys", "resultCode: " + resultCode);
        switch (resultCode) {
        case 0:
            Log.i("SonaSys", "User cancelled");
            break;
        case -1:
            onPhotoTaken();
            break;

        }

    }

}

protected void onPhotoTaken() {
    // Log message
    Log.i("SonaSys", "onPhotoTaken");
    taken = true;
    imgCapFlag = true;
    BitmapFactory.Options options = new BitmapFactory.Options();
    options.inSampleSize = 4;
    bitmap = BitmapFactory.decodeFile(path, options);
    image.setImageBitmap(bitmap);


}

回复于 2024-05-17T10:48:18+08:00

如何从我的应用程序的库（SD卡）中选择图像？

10 回答

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