如何在android M上请求访问图库的权限？

Question

我有一个应用程序，将选择图像到画廊，并显示它的测试使用ImageView。我的问题是它不能在Android M上工作。我可以选择图像，但不能在我的测试中显示。他们说我需要得到允许才能在Android M上访问图像，但不知道怎么做。请帮帮忙。

Answer 1

从Android6.0(API级别23）开始，用户在应用程序运行时授予应用程序权限，而不是在安装应用程序时授予应用程序权限。

类型1-当你的应用程序请求权限时，系统会向用户呈现一个对话框。当用户响应时，系统调用应用程序的onRequestPermissionsResult（）方法，将用户响应传递给它。您的应用程序必须重写该方法，以查明是否授予了权限。向回调传递的请求代码与您传递给requestPermissions（）的请求代码相同。

private static final int PICK_FROM_GALLERY = 1;

ChoosePhoto.setOnClickListener(new View.OnClickListener()
{
    @Override
    public void onClick (View v){
    try {
        if (ActivityCompat.checkSelfPermission(EditProfileActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            ActivityCompat.requestPermissions(EditProfileActivity.this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE, Manifest.permission.WRITE_EXTERNAL_STORAGE}, PICK_FROM_GALLERY);
        } else {
            Intent galleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
            startActivityForResult(galleryIntent, PICK_FROM_GALLERY);
        }
    } catch (Exception e) {
        e.printStackTrace();
    }
  }
});


@Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults)
    {
       switch (requestCode) {
            case PICK_FROM_GALLERY:
                // If request is cancelled, the result arrays are empty.
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                  Intent galleryIntent = new Intent(Intent.ACTION_PICK, android.provider.MediaStore.Images.Media.EXTERNAL_CONTENT_URI);
                  startActivityForResult(galleryIntent, PICK_FROM_GALLERY);
                } else {
                    //do something like displaying a message that he didn`t allow the app to access gallery and you wont be able to let him select from gallery
                }
                break;
        }
    }

类型2-如果您想在一个地方背靠背地授予运行时权限，那么您可以遵循下面的链接

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />

注意-如果manifest.permission.read_external_storage产生错误，请将其替换为android.manifest.permission.read_external_storage。

==>如果您想了解更多有关运行时权限的信息，请访问下面的链接

https://developer.android.com/training/permissions/requesting.html

 dependencies {
// For developers using AndroidX in their applications
implementation 'pub.devrel:easypermissions:3.0.0'

// For developers using the Android Support Library
implementation 'pub.devrel:easypermissions:2.0.1'
}

 @Override
     public void onRequestPermissionsResult(int requestCode, String[] 
    permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions,grantResults);

        // Forward results to EasyPermissions
        EasyPermissions.onRequestPermissionsResult(requestCode, permissions, grantResults, this);
    }

请求权限

private static final int LOCATION_REQUEST = 222;

调用此方法

@AfterPermissionGranted(LOCATION_REQUEST)
private void checkLocationRequest() {
   String[] perms = {Manifest.permission.ACCESS_FINE_LOCATION};
    if (EasyPermissions.hasPermissions(this, perms)) {
        // Already have permission, do the thing
        // ...
    } else {
        // Do not have permissions, request them now
        EasyPermissions.requestPermissions(this,"Please grant permission",
                LOCATION_REQUEST, perms);
    }
}

可选地，对于更精细的控件，您可以让您的活动/片段实现PermissionCallbacks接口。

 @Override
public void onPermissionsGranted(int requestCode, List<String> list) {
    // Some permissions have been granted
    // ...
}

@Override
public void onPermissionsDenied(int requestCode, List<String> list) {
    // Some permissions have been denied
    // ...
}

implementation 'com.github.florent37:runtime-permission-kotlin:1.1.2'

        askPermission(
        Manifest.permission.CAMERA,
        Manifest.permission.READ_EXTERNAL_STORAGE,
        Manifest.permission.WRITE_EXTERNAL_STORAGE
    ) {
       // camera or gallery or TODO
    }.onDeclined { e ->
        if (e.hasDenied()) {
            AlertDialog.Builder(this)
                .setMessage(getString(R.string.grant_permission))
                .setPositiveButton(getString(R.string.yes)) { dialog, which ->
                    e.askAgain()
                } //ask again
                .setNegativeButton(getString(R.string.no)) { dialog, which ->
                    dialog.dismiss()
                }
                .show()
        }

        if (e.hasForeverDenied()) {
            e.goToSettings()
        }
    }

链接->https://github.com/florent37/runtimepermission