位置权限编译错误答案

【问题标题】：Location permission compilation error位置权限编译错误
【发布时间】：2017-08-02 23:32:44
【问题描述】：

我确定我在这里获得了许可：

private void checkPermissions() {
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION}, PERMISSION_LOCATION_REQUEST_CODE);
    } else {
        getLocation();
    }
}

private void getLocation() {
    LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
    LocationListener locationListener = new UserLocationListener();
    locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 10, this);
}

但我仍然收到 requestLocationUpdates() 调用的编译错误：

Call requires permission which may be rejected by user: code should explicitly check to see if permission is available (with `checkPermission`) or explicitly handle a potential `SecurityException`

当我像这样删除函数调用时，错误得到解决：

private void checkPermissions() {
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_FINE_LOCATION)
            != PackageManager.PERMISSION_GRANTED && ActivityCompat.checkSelfPermission(this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
        ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION}, PERMISSION_LOCATION_REQUEST_CODE);
    } else {
        LocationManager locationManager = (LocationManager) this.getSystemService(Context.LOCATION_SERVICE);
        LocationListener locationListener = new UserLocationListener();
        locationManager.requestLocationUpdates(LocationManager.GPS_PROVIDER, 5000, 10, this);
    }
}

不过我还需要在 onRequestPermissionsResult 回调中调用 getLocation 函数，所以我想保留它。

清单：

<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.ACCESS_COARSE_LOCATION" />
<uses-permission android:name="android.permission.ACCESS_FINE_LOCATION" />
<!-- Needed only if your app targets Android 5.0 (API level 21) or higher. -->
<uses-feature android:name="android.hardware.location.gps" />

这通常是如何解决的？

【问题讨论】：

标签： android android-permissions android-gps runtime-permissions

【解决方案1】：

像这样管理这些权限是一场噩梦。我建议你使用这个库来处理所有样板文件。只需很少的 RXJava 知识就可以做到这一点 https://github.com/tbruyelle/RxPermissions

compile 'com.tbruyelle.rxpermissions:rxpermissions:0.9.3@aar'

然后：

final String permission = Manifest.permission.ACCESS_FINE_LOCATION;
rxPermissions
.request(permission)
.switchMap(new Func1<Boolean, Observable<Boolean>>() {
    @Override
    public Observable<Boolean> call(Boolean permissionGranted) {
        if (permissionGranted) {
            //todo: do stuff require permissions.
        } else {
            rxPermissions.shouldShowRequestPermissionRationale(activity, permission).switchMap(
            new Func1<Boolean, Observable<Boolean>>() {
                @Override
                public Observable<Boolean> call(Boolean canShowRationale) {
                    if (canShowRationale) {
                        /**
                         * when user deny permission,Show dialog explaining why permission is
                         * necessary. On Selecting Ask again, permission access will be
                         * re-requested.
                         */

                        //todo: 
                    } else {
                        /**
                         * When user deny permission and select Never Ask Again, Show dialog
                         * explaining why permission are necessary. In this case user need to
                         * go to settings and grant permission.
                         */

                        //todo: 
                    }
                }
            });
          }
    }
});

【讨论】：

太棒了。我很想看看，但我的老板讨厌任何第三方。
嗯，好的。我刚刚修改了带有位置请求的示例
“我的老板讨厌任何第三方”。除非您在一个非常特殊的环境中工作，证明这种厌恶是合理的，否则您的老板需要意识到所有应用程序都使用第三方库，这是快速发布内容的唯一方法，并且需要更少的代码来维护自己。

【解决方案2】：

对于非反应式方法，这个库将非常有帮助，它使用简单的基于注释的 API 来处理运行时权限：

https://github.com/hotchemi/PermissionsDispatcher

@RuntimePermissions
public class MainActivity extends AppCompatActivity {

    @NeedsPermission(Manifest.permission.CAMERA)
    void showCamera() {
        getSupportFragmentManager().beginTransaction()
                .replace(R.id.sample_content_fragment, CameraPreviewFragment.newInstance())
                .addToBackStack("camera")
                .commitAllowingStateLoss();
    }

    @OnShowRationale(Manifest.permission.CAMERA)
    void showRationaleForCamera(final PermissionRequest request) {
        new AlertDialog.Builder(this)
            .setMessage(R.string.permission_camera_rationale)
            .setPositiveButton(R.string.button_allow, (dialog, button) -> request.proceed())
            .setNegativeButton(R.string.button_deny, (dialog, button) -> request.cancel())
            .show();
    }

    @OnPermissionDenied(Manifest.permission.CAMERA)
    void showDeniedForCamera() {
        Toast.makeText(this, R.string.permission_camera_denied, Toast.LENGTH_SHORT).show();
    }

    @OnNeverAskAgain(Manifest.permission.CAMERA)
    void showNeverAskForCamera() {
        Toast.makeText(this, R.string.permission_camera_neverask, Toast.LENGTH_SHORT).show();
    }
}

【讨论】：