Question

我是Android的新手，我想在按钮点击中获取当前位置。我正在关注this documentation。单击相应按钮时，我正在调用public void showLocation(View v)。我已经尝试过一块一块来测试它。以下是我的调查。

要测试函数调用和权限检查， 我收到来自以下函数的GRANTED消息

public void showLocation(View v) {
    int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
    if( permissionCheck != PackageManager.PERMISSION_GRANTED ) {
        Toast.makeText(getApplicationContext(), "Granted", Toast.LENGTH_SHORT).show();
    }
    else {
        Toast.makeText(getApplicationContext(), "Permission Not Granted", Toast.LENGTH_SHORT).show();
    }
}

要测试mFusedLocationClient.getLastLocation().addOnSuccessListener， 我的申请不幸在此停止

public void showLocation(View v) {
    int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION);
    if( permissionCheck != PackageManager.PERMISSION_GRANTED ) {
        mFusedLocationClient.getLastLocation()
                .addOnSuccessListener(this, new OnSuccessListener<Location>() {
                    @Override
                    public void onSuccess(Location location) {
                        Toast.makeText(getApplicationContext(), "hello there", Toast.LENGTH_SHORT).show();
                    }
                });
    }
    else {
        Toast.makeText(getApplicationContext(), "Permission Not Granted", Toast.LENGTH_SHORT).show();
    }
}

Answer 1

你做错了。首先。想想你写的这个条件。

if( permissionCheck != PackageManager.PERMISSION_GRANTED )

因此，如果未授予许可，则您要求提供您的位置。

而不是你应该从用户那里请求权限。

requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION},
            MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION);

并且在此您可以获得结果

@Override
    public void onRequestPermissionsResult(int requestCode,
            String permissions[], int[] grantResults) {
        switch (requestCode) {
            case MY_PERMISSIONS_REQUEST_ACCESS_FINE_LOCATION: {
                if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {

                    // permission was granted, yay! do that


                } else {

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

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

所以你只需要正确获得运行时权限。没有别的

编辑：根据您的评论您可以执行以下操作。

yourbutton .setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {

               //First of All check for permission .
                  askForPermission(Manifest.permission.ACCESS_FINE_LOCATION, READ_EXST);
            }
        });


private void askForPermission(String permission, Integer requestCode) {
        if (ContextCompat.checkSelfPermission(UserActivity.this, permission) != PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(UserActivity.this, permission)) {
                //This is called if user has denied the permission before
                //In this case I am just asking the permission again
                ActivityCompat.requestPermissions(UserActivity.this, new String[]{permission}, requestCode);
            } else {

                ActivityCompat.requestPermissions(UserActivity.this, new String[]{permission}, requestCode);
            }
        } else {

            //FETCH USER LOCATION HERE
        }
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        if (ActivityCompat.checkSelfPermission(this, permissions[0]) == PackageManager.PERMISSION_GRANTED) {
            Toast.makeText(this, "Permission granted", Toast.LENGTH_SHORT).show();
          //FETCH USER LOCATION HERE 
        } else {

            Toast.makeText(this, "Permission denied", Toast.LENGTH_SHORT).show();
        }
    }

Android获取当前位置无效

1 个答案: