Question

我是初学者在android中使用图像。我想从内部存储加载图像但它给我权限被拒绝错误然后我已经添加了对android清单文件的权限。但我仍然无法完成任务。

这是我的代码：

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ImageView image = (ImageView)findViewById(R.id.imageView);
        Bitmap bm = BitmapFactory.decodeFile("/storage/emulated/0/DCIM/Camera/IMG_20151102_193132.jpg");
        image.setImageBitmap(bm);

    }
}

logcat的：

01-16 15:16:11.345 6533-6533/com.example.jaytanna.imagemap E/BitmapFactory: Unable to decode stream: java.io.FileNotFoundException: /storage/emulated/0/DCIM/Camera/IMG_20151102_193132.jpg: open failed: EACCES (Permission denied)

没有显示任何图像。请帮助我。谢谢。

Answer 1

检查

     File imgFile = new  File("/storage/emulated/0/DCIM/Camera/IMG_20151102_193132.jpg");
      if(imgFile.exists()){

        Bitmap myBitmap = BitmapFactory.decodeFile(imgFile.getAbsolutePath());

        ImageView myImage = (ImageView) findViewById(R.id.imageviewTest);

        myImage.setImageBitmap(myBitmap);

      };

并在清单文件中包含此权限：

<manifest>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
    ...
    <application>
        ...
        <activity> 
            ...
        </activity>
    </application>
</manifest>

对于API 23+，您需要请求读/写权限，即使它们已经在您的清单中。

// Storage Permissions
private static final int REQUEST_EXTERNAL_STORAGE = 1;
private static String[] PERMISSIONS_STORAGE = {
        Manifest.permission.READ_EXTERNAL_STORAGE,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
};

/**
 * Checks if the app has permission to write to device storage
 *
 * If the app does not has permission then the user will be prompted to grant permissions
 *
 * @param activity
 */
public static void verifyStoragePermissions(Activity activity) {
    // Check if we have write permission
    int permission = ActivityCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);

    if (permission != PackageManager.PERMISSION_GRANTED) {
        // We don't have permission so prompt the user
        ActivityCompat.requestPermissions(
                activity,
                PERMISSIONS_STORAGE,
                REQUEST_EXTERNAL_STORAGE
        );
    }
}

并处理响应，例如：

@Override
public void onRequestPermissionsResult(int requestCode,
        String permissions[], int[] grantResults) {
    switch (requestCode) {
        case MY_PERMISSIONS_REQUEST_READ_CONTACTS: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                // permission was granted, yay! Do the
                // contacts-related task you need to do.

            } else {

                // permission denied, boo! Disable the
                // functionality that depends on this permission.
            }
            return;
        }

        // other 'case' lines to check for other
        // permissions this app might request
    }
}

有关申请API 23+权限的官方文档，请查看https://developer.android.com/training/permissions/requesting.html

Answer 2

你需要像这样添加运行时permisssion检查：

    public  boolean isStoragePermissionGranted() {
    if (Build.VERSION.SDK_INT >= 23) {
        if (checkSelfPermission(android.Manifest.permission.READ_EXTERNAL_STORAGE)
                == PackageManager.PERMISSION_GRANTED) {
            Log.v(TAG,"Permission is granted");
            return true;
        } else {

            Log.v(TAG,"Permission is revoked");
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
            return false;
        }
    }
    else { //permission is automatically granted on sdk<23 upon installation
        Log.v(TAG,"Permission is granted");
        return true;
    }
}

使用它像：

if(isStoragePermissionGranted()){
 Bitmap bm = BitmapFactory.decodeFile("/storage/emulated/0/DCIM/Camera/IMG_20151102_193132.jpg");
 image.setImageBitmap(bm);

 }

抓住结果

    @Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    if(grantResults[0]== PackageManager.PERMISSION_GRANTED){
        Log.v(TAG,"Permission: "+permissions[0]+ "was "+grantResults[0]);
        //resume tasks needing this permission
        Bitmap bm = BitmapFactory.decodeFile("/storage/emulated/0/DCIM/Camera/IMG_20151102_193132.jpg");
       image.setImageBitmap(bm);
    }
}

Answer 3

您是否在应用设置中启用了权限？（READ_EXTERNAL_STORAGE或WRITE_EXTERNAL_STORAGE都会显示为“storage”

Answer 4

Intent gallery = new Intent(Intent.ACTION_PICK, MediaStore.Images.Media.INTERNAL_CONTENT_URI);
        startActivityForResult(gallery,PICK_IMAGE);

@Override
    protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
        super.onActivityResult(requestCode, resultCode, data);
        if(resultCode == RESULT_OK && requestCode == PICK_IMAGE){
         imageUri = data.getData();
         imageView.setImageURI(imageUri);
        }
    }

这将起作用。简单而简单

如何在imageView上显示从内部存储中选择的图像？

4 个答案: