## Usage with Java

Here's a minimum example, in which you register a `MainActivity` which requires `Manifest.permission.CAMERA`.

### 0. Prepare AndroidManifest

Add the following line to `AndroidManifest.xml`:
 
`<uses-permission android:name="android.permission.CAMERA" />`

### 1. Attach annotations

PermissionsDispatcher introduces only a few annotations, keeping its general API concise:

> NOTE: Annotated methods must not be `private`.

|Annotation|Required|Description|
|---|---|---|
|`@RuntimePermissions`|**✓**|Register an `Activity` or `Fragment` to handle permissions|
|`@NeedsPermission`|**✓**|Annotate a method which performs the action that requires one or more permissions|
|`@OnShowRationale`||Annotate a method which explains why the permissions are needed. It passes in a `PermissionRequest` object which can be used to continue or abort the current permission request upon user input. If you don't specify any argument for the method compiler will generate `process${NeedsPermissionMethodName}ProcessRequest` and `cancel${NeedsPermissionMethodName}ProcessRequest`. You can use those methods in place of `PermissionRequest`(ex: with `DialogFragment`)|
|`@OnPermissionDenied`||Annotate a method which is invoked if the user doesn't grant the permissions|
|`@OnNeverAskAgain`||Annotate a method which is invoked if the user chose to have the device "never ask again" about a permission|

```java
@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();
    }
}
```

### 2. Delegate to generated class

Upon compilation, PermissionsDispatcher generates a class for `MainActivityPermissionsDispatcher`([Activity Name] + PermissionsDispatcher), which you can use to safely access these permission-protected methods.

The only step you have to do is delegating the work to this helper class:

```java
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    findViewById(R.id.button_camera).setOnClickListener(v -> {
      // NOTE: delegate the permission handling to generated method
      MainActivityPermissionsDispatcher.showCameraWithPermissionCheck(this);
    });
}

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    // NOTE: delegate the permission handling to generated method
    MainActivityPermissionsDispatcher.onRequestPermissionsResult(this, requestCode, grantResults);
}
```

Check out the [sample](https://github.com/hotchemi/PermissionsDispatcher/tree/master/sample) for more details.