如果之前没有授予或拒绝权限，如何每次请求活动启动权限

Question

我正在开发一个需要用户位置的android应用程序，每次用户登录到该应用程序。

我已经写了代码来获取用户位置和工作良好，但问题是，如果用户拒绝权限两次，它没有再问，这是我的代码:

public class MainActivity extends AppCompatActivity {
String myLocation = "";
private LocationRequest locationRequest;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
locationRequest = LocationRequest.create();
locationRequest.setPriority(LocationRequest.PRIORITY_HIGH_ACCURACY);
locationRequest.setInterval(5000);
locationRequest.setFastestInterval(2000);
getCurrentLocation();
}
@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
super.onRequestPermissionsResult(requestCode, permissions, grantResults);
if (requestCode == 1) {
if (grantResults[0] == PackageManager.PERMISSION_GRANTED) {
if (isGPSEnabled()) {
getCurrentLocation();
} else {
turnOnGPS();
}
}
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode, @Nullable Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (requestCode == 2) {
if (resultCode == Activity.RESULT_OK) {
getCurrentLocation();
}
}
}
private void getCurrentLocation() {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
if (ActivityCompat.checkSelfPermission(MainActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) == PackageManager.PERMISSION_GRANTED) {
if (isGPSEnabled()) {
LocationServices.getFusedLocationProviderClient(MainActivity.this)
.requestLocationUpdates(locationRequest, new LocationCallback() {
@Override
public void onLocationResult(@NonNull LocationResult locationResult) {
super.onLocationResult(locationResult);
LocationServices.getFusedLocationProviderClient(MainActivity.this)
.removeLocationUpdates(this);
if (locationResult != null && locationResult.getLocations().size() > 0) {
int index = locationResult.getLocations().size() - 1;
double latitude = locationResult.getLocations().get(index).getLatitude();
double longitude = locationResult.getLocations().get(index).getLongitude();
myLocation = "Latitude: " + latitude + " Longitude: " + longitude;
Toast.makeText(getApplicationContext(), myLocation, Toast.LENGTH_LONG).show();
}
}
}, Looper.getMainLooper());
} else {
turnOnGPS();
}
} else {
requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION}, 1);
}
}
}
private void turnOnGPS() {
LocationSettingsRequest.Builder builder = new LocationSettingsRequest.Builder().addLocationRequest(locationRequest);
builder.setAlwaysShow(true);
Task<LocationSettingsResponse> result = LocationServices.getSettingsClient(getApplicationContext())
.checkLocationSettings(builder.build());
result.addOnCompleteListener(new OnCompleteListener<LocationSettingsResponse>() {
@Override
public void onComplete(@NonNull Task<LocationSettingsResponse> task) {
try {
LocationSettingsResponse response = task.getResult(ApiException.class);
Toast.makeText(MainActivity.this, "GPS is already tured on", Toast.LENGTH_SHORT).show();
} catch (ApiException e) {
switch (e.getStatusCode()) {
case LocationSettingsStatusCodes.RESOLUTION_REQUIRED:
try {
ResolvableApiException resolvableApiException = (ResolvableApiException) e;
resolvableApiException.startResolutionForResult(MainActivity.this, 2);
} catch (IntentSender.SendIntentException ex) {
ex.printStackTrace();
}
break;
case LocationSettingsStatusCodes.SETTINGS_CHANGE_UNAVAILABLE:
//Device does not have location
break;
}
}
}
});
}
private boolean isGPSEnabled() {
LocationManager locationManager = null;
boolean isEnabled = false;
if (locationManager == null) {
locationManager = (LocationManager) getSystemService(Context.LOCATION_SERVICE);
}
isEnabled = locationManager.isProviderEnabled(LocationManager.GPS_PROVIDER);
return isEnabled;
}
}  

作为，用户的位置是必须的应用程序的工作。现在，我希望应用程序:

1-请求活动开始的许可，如果之前没有授予或拒绝许可。
2-如果获得许可，则继续执行，否则关闭活动。

那么，我怎样才能做到这一点呢?由于

Answer 1

但问题是，如果用户拒绝权限两次，它没有要求再次,

是的，如果用户拒绝使用"Don't ask again&;"检查。默认情况下，在第二个权限请求时通常选中此复选框。注意，在api 11中，没有复选框，拒绝是自动拒绝自动重置的。

方法是，你不假设什么，只是把处理它的逻辑。如果拒绝，您只能告知用户所需的权限。官方文件说:ref

如果ContextCompat.checkSelfPermission()方法返回PERMISSION_DENIED，调用shouldShowRequestPermissionRationale()。如果这个方法返回true，向用户显示一个教育UI。在这个UI，描述为什么用户想要启用的特性需要一个特定的许可。

信息

Answer 2

您可以检查用户是否已经使用checkSelfPermission授予权限，如果没有，则再次请求权限，否则使用程序流处理。

if (ContextCompat.checkSelfPermission(this,Manifest.permission.READ_EXTERNAL_STORAGE)
== PackageManager.PERMISSION_GRANTED){
doStuff()
} else {

requestStoragePermission()
}