Android 如何为我的应用从图库（SD 卡）中选择图像？

How to pick an image from gallery (SD Card) for my app?

提问by Praveen

This question was originally asked for Android 1.6.

这个问题最初是针对 Android 1.6 提出的。

I am working on photos options in my app.

我正在我的应用程序中处理照片选项。

I have a button and an ImageView in my Activity. When I click the button it would redirect to the gallery and I would be able to select an image. The selected image would appear in my ImageView.

我的活动中有一个按钮和一个 ImageView。当我单击按钮时，它会重定向到图库，我将能够选择图像。所选图像将出现在我的 ImageView 中。

回答by Steve Haley

Updated answer, nearly 5 years later:

近 5 年后更新的答案：

The code in the original answer no longer works reliably, as images from various sources sometimes return with a different content URI, i.e. content://rather than file://. A better solution is to simply use context.getContentResolver().openInputStream(intent.getData()), as that will return an InputStream that you can handle as you choose.

原始答案中的代码不再可靠地工作，因为来自不同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())，因为这将返回一个您可以选择处理的 InputStream 。

For example, BitmapFactory.decodeStream()works perfectly in this situation, as you can also then use the Options and inSampleSize field to downsample large images and avoid memory problems.

例如，BitmapFactory.decodeStream()在这种情况下效果很好，因为您还可以使用 Options 和 inSampleSize 字段对大图像进行下采样并避免内存问题。

However, things like Google Drive return URIs to images which have not actually been downloaded yet. Therefore you need to perform the getContentResolver() code on a background thread.

但是，Google Drive 之类的东西会将 URI 返回到尚未实际下载的图像。因此，您需要在后台线程上执行 getContentResolver() 代码。

---

---

Original answer:

原答案：

The other answers explained how to send the intent, but they didn't explain well how to handle the response. Here's some sample code on how to do that:

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一些示例代码：

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);
        }
    }
}

After this, you've got the selected image stored in "yourSelectedImage" to do whatever you want with. This code works by getting the location of the image in the ContentResolver database, but that on its own isn't enough. Each image has about 18 columns of information, ranging from its filepath to 'date last modified' to the GPS coordinates of where the photo was taken, though many of the fields aren't actually used.

在此之后，您已将选定的图像存储在“yourSelectedImage”中，以执行您想要的任何操作。此代码通过获取图像在 ContentResolver 数据库中的位置来工作，但仅靠它是不够的。每张图像都有大约 18 列信息，范围从其文件路径到“上次修改日期”，再到照片拍摄地点的 GPS 坐标，尽管许多字段实际上并未使用。

To save time as you don't actually need the other fields, cursor search is done with a filter. The filter works by specifying the name of the column you want, MediaStore.Images.Media.DATA, which is the path, and then giving that string[] to the cursor query. The cursor query returns with the path, but you don't know which column it's in until you use the columnIndexcode. That simply gets the number of the column based on its name, the same one used in the filtering process. Once you've got that, you're finally able to decode the image into a bitmap with the last line of code I gave.

为了节省时间，因为您实际上不需要其他字段，光标搜索使用过滤器完成。过滤器的工作方式是指定所需列的名称 MediaStore.Images.Media.DATA，即路径，然后将该字符串 [] 提供给游标查询。游标查询返回路径，但在使用columnIndex代码之前，您不知道它位于哪一列。这只是根据名称获取列的编号，与过滤过程中使用的编号相同。一旦你有了它，你终于能够用我给出的最后一行代码将图像解码成位图。

回答by siamii

private static final int SELECT_PHOTO = 100;

Start intent

开始意图

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

Process result

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);
        }
    }
}

Alternatively, you can also downsample your image to avoid OutOfMemory errors.

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);

    }

回答by Robby Pond

You have to start the gallery intent for a result.

您必须启动图库意图才能获得结果。

Intent i = new Intent(Intent.ACTION_PICK,
               android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
startActivityForResult(i, ACTIVITY_SELECT_IMAGE); 

Then in onActivityForResult, call intent.getData()to get the Uri of the Image. Then you need to get the Image from the ContentProvider.

然后在 中onActivityForResult，调用intent.getData()以获取图像的 Uri。然后您需要从 ContentProvider 获取图像。

回答by Muhammad Umair Shafique

Here is a tested code for image and video.It will work for all APIs less than 19 and greater than 19 as well.

这是一个经过测试的图像和视频代码。它适用于小于 19 和大于 19 的所有 API。

Image:

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);
                    }

Video:

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();
        }

回答by Mark B

Do this to launch the gallery and allow the user to pick an image:

执行此操作以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);

Then in your onActivityResult()use the URI of the image that is returned to set the image on your ImageView.

然后在您onActivityResult()使用返回的图像的 URI 中设置 ImageView 上的图像。

回答by Sheetal More

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);
}

}

回答by Muhammad Usman Ghani

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();
}

}

回答by Andy Res

For some reasons, all of the answers in this thread, in onActivityResult()try to post-process the received Uri, like getting the real path of the image and then use BitmapFactory.decodeFile(path)to get the Bitmap.

由于种种原因，都在这个线程的答案，在onActivityResult()尝试后处理接收到的Uri，就像得到了图像的真实路径，然后用BitmapFactory.decodeFile(path)得到的Bitmap。

This step is unnecessary. The ImageViewclass has a method called setImageURI(uri). Pass your uri to it and you should be done.

这一步是不必要的。该ImageView班有一个叫方法setImageURI(uri)。将你的 uri 传递给它，你应该完成。

Uri imageUri = data.getData();
imageView.setImageURI(imageUri);

For a complete working example you could take a look here: http://androidbitmaps.blogspot.com/2015/04/loading-images-in-android-part-iii-pick.html

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:
Getting the Bitmapin a separate variable would make sense in cases where the image to be loaded is too large to fit in memory, and a scale down operation is necessary to prevent OurOfMemoryError, like shown in the @siamii answer.

PS：在要加载的图像太大而无法放入内存的情况下，
获取Bitmap单独的变量是有意义的，并且需要按比例缩小操作以防止OurOfMemoryError，如@siamii 答案中所示。

回答by Akshay Paliwal

call chooseImage method like-

调用 chooseImage 方法，例如-

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();
    }
}

回答by ASHISH KUMAR Tiwary

#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);


}