我有这个应用程序,它将图像选择到画廊,并使用Imageview将其显示给测试。我的问题是它不能在Android M上运行。我可以选择图像但不能在测试中显示。他们说我需要请求访问android M上图像的权限,但不知道如何操作。请帮忙。

最佳答案

从Android 6.0(API级别23)开始,用户在应用程序运行时(而不是在安装应用程序时)授予应用程序权限。
类型1- 当您的应用请求权限时,系统会向用户显示一个对话框。当用户响应时,系统会调用您应用的onRequestPermissionsResult()方法,并将用户响应传递给该方法。您的应用必须重写该方法才能确定是否已授予权限。回调传递给您的请求代码与传递给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授予运行时权限,则可以点击以下链接
Android 6.0 multiple permissions
并在 list 中添加您的要求的权限
<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-如果Manifest.permission.READ_EXTERNAL_STORAGE产生错误,则将其替换为android.Manifest.permission.READ_EXTERNAL_STORAGE。
==> 如果您想了解更多有关运行时权限的信息,请点击以下链接
https://developer.android.com/training/permissions/requesting.html
-----------------------------更新1 ------------------ --------------
使用EasyPermissions的运行时权限
EasyPermissions是一个包装器库,用于简化针对Android M或更高版本的基本系统权限逻辑。
安装
在应用程序级别gradle中添加依赖项
 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'
}
您的 Activity (或片段)将覆盖onRequestPermissionsResult方法:
 @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)为得到更好的控制,您可以让Activity/Fragment实现PermissionCallbacks接口(interface)。
实现EasyPermissions.PermissionCallbacks
 @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
    // ...
}
链接-> https://github.com/googlesamples/easypermissions
-----------------------------更新2适用于KOTLIN ---------------- ----------------
使用florent37的运行时权限
安装在应用程序级别gradle中添加依赖项
依赖性
implementation 'com.github.florent37:runtime-permission-kotlin:1.1.2'
在代码中
        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

10-06 10:22
查看更多