如果用户第一次拒绝，如何再次请求权限（RunTime）

Question

如果他/她第一次拒绝，我想重新向这种情况下的用户请求许可。我已经设置了权限，但即使我按下 deny 选项，我的应用程序也会运行。我有一个代码应该做我想做的事情，但是当我点击 Alt+Enter 时我得到 Cant resolve symbol Snackbar 它创建了另一个活动并剩下 -make 和-permision_available_camera 出现红色错误。

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

        if (requestCode == REQUEST_CAMERA) {
            // BEGIN_INCLUDE(permission_result)
            // Received permission result for camera permission.
            Log.i(TAG, "Received response for Camera permission request.");

            // Check if the only required permission has been granted
            if (grantResults.length == 1 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                // Camera permission has been granted, preview can be displayed
                Log.i(TAG, "CAMERA permission has now been granted. Showing preview.");
                Snackbar.make(mLayout, R.string.permision_available_camera,
                        Snackbar.LENGTH_SHORT).show();
            } else {
                Log.i(TAG, "CAMERA permission was NOT granted.");
                Snackbar.make(mLayout, R.string.permissions_not_granted,
                        Snackbar.LENGTH_SHORT).show();

            }

Answer 1

试试这个

基本上，我们在这里尝试从外部存储中读取内容。为此，我们必须向用户询问运行时权限。如果用户允许它很好，但如果用户拒绝该权限，它将显示第二个对话框/消息框，直到用户接受该权限

1. 请求许可

1. 如果用户拒绝，它将在用户启动应用程序时显示“需要权限”对话框

1. 如果用户按下确定按钮，它将再次请求权限。

 public class MainActivity extends AppCompatActivity {

        public static int REQUEST_PERMISSION=1;
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);

            permission_fn();


        }

        private  void requestStoragePermission()
        {
            if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.READ_EXTERNAL_STORAGE))
            {
                new AlertDialog.Builder(this)
                        .setTitle("Permission Needed")
                        .setMessage("Permission is needed to access files from your device...")
                        .setPositiveButton("OK", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                ActivityCompat.requestPermissions(MainActivity.this,new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},REQUEST_PERMISSION);
                            }
                        })
                        .setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
                            @Override
                            public void onClick(DialogInterface dialog, int which) {
                                dialog.dismiss();
                            }
                        }).create().show();
            }
            else
            {
                ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},REQUEST_PERMISSION);
            }
        }

        private void permission_fn()
        {
            if(ContextCompat.checkSelfPermission(MainActivity.this,Manifest.permission.READ_EXTERNAL_STORAGE)== PackageManager.PERMISSION_GRANTED)
            {
                if(ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this, Manifest.permission.READ_EXTERNAL_STORAGE))
                {

                }
                else
                {
                    ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},REQUEST_PERMISSION);
                }
            }
            else {

                requestStoragePermission();

            }
        }

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

                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    Toast.makeText(this, "Thanks for enabling the permission", Toast.LENGTH_SHORT).show();

                    //do something permission is allowed here....

                } else {

                    Toast.makeText(this, "Please allow the Permission", Toast.LENGTH_SHORT).show();


                }
            }

        }


        }

在 AndroidManifest.xml 文件中添加用户权限

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

Answer 2

@Arjun Thakun 这里是一种管理再次询问权限概念的方法，并处理当应用询问权限时用户可以回答的所有方式

       if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        if (checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
            //.... write file into storage ...
            System.out.println("SDK > BuildVersion TRUE");
        } else {
            requestPermissions(new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 666);  // Comment 26
            System.out.println("go to requestPermissions");
        }
    }
    onLoad();
}

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

    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    switch (requestCode) {

        case 666: // Allowed was selected so Permission granted
            if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                Snackbar s = Snackbar.make(findViewById(android.R.id.content),"Permission Granted",Snackbar.LENGTH_LONG);
                View snackbarView = s.getView();
                TextView textView = (TextView) snackbarView.findViewById(android.support.design.R.id.snackbar_text);
                textView.setTextColor(Color.RED);
                textView.setTextSize(18);
                textView.setMaxLines(6);
                s.show();

                // do your work here

            } else if (Build.VERSION.SDK_INT >= 23 && !shouldShowRequestPermissionRationale(permissions[0])) {
                // User selected the Never Ask Again Option Change settings in app settings manually
                AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
                alertDialogBuilder.setTitle("Change Permissions in Settings");
                alertDialogBuilder
                        .setMessage("" +
                                "\nClick SETTINGS to Manually Set\n"+"Permissions to use Database Storage")
                        .setCancelable(false)
                        .setPositiveButton("SETTINGS", new DialogInterface.OnClickListener() {
                            public void onClick(DialogInterface dialog, int id) {
                                Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                                Uri uri = Uri.fromParts("package", getPackageName(), null);
                                intent.setData(uri);
                                startActivityForResult(intent, 1000);     // Comment 3.
                            }
                        });

                AlertDialog alertDialog = alertDialogBuilder.create();
                alertDialog.show();

            } else {
                    // User selected Deny Dialog to EXIT App ==> OR <== RETRY to have a second chance to Allow Permissions
                if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M && checkSelfPermission(Manifest.permission.WRITE_EXTERNAL_STORAGE) == PackageManager.PERMISSION_DENIED) {

                    AlertDialog.Builder alertDialogBuilder = new AlertDialog.Builder(this);
                    alertDialogBuilder.setTitle("Second Chance");
                    alertDialogBuilder
                            .setMessage("Click RETRY to Set Permissions to Allow\n\n"+"Click EXIT to the Close App")
                            .setCancelable(false)
                            .setPositiveButton("RETRY", new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    //ActivityCompat.requestPermissions((Activity) context, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, Integer.parseInt(WRITE_EXTERNAL_STORAGE));
                                    Intent i = new Intent(MainActivity.this,MainActivity.class);
                                    i.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP | Intent.FLAG_ACTIVITY_NEW_TASK);
                                    startActivity(i);
                                    }
                            })
                            .setNegativeButton("EXIT", new DialogInterface.OnClickListener() {
                                public void onClick(DialogInterface dialog, int id) {
                                    finish();
                                    dialog.cancel();
                                }
                            });
                    AlertDialog alertDialog = alertDialogBuilder.create();
                    alertDialog.show();
                }
            }
            break;
    }};