PermissionsDispatcher使用详解

PermissionsDispatcher是一个基于注解、帮助开发者简单处理Android 6.0系统中的运行时权限的开源库。避免了开发者编写大量繁琐的样板代码。

开源地址：https://github.com/hotchemi/PermissionsDispatcher

文档介绍：http://hotchemi.github.io/PermissionsDispatcher/

下面详细介绍一下如何在Android Studio上使用该开源库。

1、添加依赖

首先在项目工程下的build.gradle文件中加入对maven仓库依赖引入的支持。

allprojects {
    repositories {
        jcenter()
        mavenCentral()
    }
}

之后在module下的build.gradle文件中添加两项依赖：

compile 'com.github.hotchemi:permissionsdispatcher:2.3.1'
annotationProcessor 'com.github.hotchemi:permissionsdispatcher-processor:2.3.1'

并将targetSdkVersion设为23，即：targetSdkVersion 23

2、在Activity或Fragment中使用

注解列表：

Annotation	Required	Description
@RuntimePermissions	✓	注解在其内部需要使用运行时权限的Activity或Fragment上
@NeedsPermission	✓	注解在需要调用运行时权限的方法上，当用户给予权限时会执行该方法
@OnShowRationale		注解在用于向用户解释为什么需要调用该权限的方法上，只有当第一次请求权限被用户拒绝，下次请求权限之前会调用
@OnPermissionDenied		注解在当用户拒绝了权限请求时需要调用的方法上
@OnNeverAskAgain		注解在当用户选中了授权窗口中的不再询问复选框后并拒绝了权限请求时需要调用的方法，一般可以向用户解释为何申请此权限，并根据实际需求决定是否再次弹出权限请求对话框

注意：被注解的方法不能是私有方法。

只有@RuntimePermissions和@NeedsPermission是必须的，其余注解均为可选。当使用了@RuntimePermissions和@NeedsPermission之后，需要点击菜单栏中Build菜单下的Make Project，或者按快捷键Ctrl + F9编译整个项目，编译器会在appuildintermediatesclassesdebug目录下与被注解的Activity同一个包下生成一个辅助类，名称为被注解的Activity名称+PermissionsDispatcher.class，如图所示：

接下来可以调用辅助类里面的方法完成应用的权限请求了。

在需要调用权限的位置调用辅助类里面的xxxWithCheck方法，xxx是被@NeedsPermission注解的方法名。如：

MainActivityPermissionsDispatcher.showCameraWithCheck(this);

之后，还需要重写该Activity的onRequestPermissionsResult()方法，其方法内调用辅助类的onRequestPermissionsResult()方法，如下：

@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);
}

完整的MainActivity如下所示。

• MainActivity.java

@RuntimePermissions
public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        findViewById(R.id.button_camera).setOnClickListener(this);
        findViewById(R.id.button_contacts).setOnClickListener(this);
    }

    @Override
    public void onClick(@NonNull View v) {
        switch (v.getId()) {
            case R.id.button_camera:
                // NOTE: delegate the permission handling to generated method
                MainActivityPermissionsDispatcher.showCameraWithCheck(this);
                break;
            case R.id.button_contacts:
                // NOTE: delegate the permission handling to generated method
                MainActivityPermissionsDispatcher.showContactsWithCheck(this);
                break;
        }
    }

    @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);
    }

    @NeedsPermission(Manifest.permission.CAMERA)
    void showCamera() {
        // NOTE: Perform action that requires the permission. If this is run by PermissionsDispatcher, the permission will have been granted
        getSupportFragmentManager().beginTransaction()
                .replace(R.id.sample_content_fragment, CameraPreviewFragment.newInstance())
                .addToBackStack("camera")
                .commitAllowingStateLoss();
    }

    @NeedsPermission({Manifest.permission.READ_CONTACTS, Manifest.permission.WRITE_CONTACTS})
    void showContacts() {
        // NOTE: Perform action that requires the permission.
        // If this is run by PermissionsDispatcher, the permission will have been granted
        getSupportFragmentManager().beginTransaction()
                .replace(R.id.sample_content_fragment, ContactsFragment.newInstance())
                .addToBackStack("contacts")
                .commitAllowingStateLoss();
    }

    @OnShowRationale(Manifest.permission.CAMERA)
    void showRationaleForCamera(PermissionRequest request) {
        // NOTE: Show a rationale to explain why the permission is needed, e.g. with a dialog.
        // Call proceed() or cancel() on the provided PermissionRequest to continue or abort
        showRationaleDialog(R.string.permission_camera_rationale, request);
    }

    @OnShowRationale({Manifest.permission.READ_CONTACTS, Manifest.permission.WRITE_CONTACTS})
    void showRationaleForContact(PermissionRequest request) {
        // NOTE: Show a rationale to explain why the permission is needed, e.g. with a dialog.
        // Call proceed() or cancel() on the provided PermissionRequest to continue or abort
        showRationaleDialog(R.string.permission_contacts_rationale, request);
    }

    @OnPermissionDenied(Manifest.permission.CAMERA)
    void onCameraDenied() {
        // NOTE: Deal with a denied permission, e.g. by showing specific UI
        // or disabling certain functionality
        Toast.makeText(this, R.string.permission_camera_denied, Toast.LENGTH_SHORT).show();
    }

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

    public void onBackClick(View view) {
        getSupportFragmentManager().popBackStack();
    }

    private void showRationaleDialog(@StringRes int messageResId, final PermissionRequest request) {
        new AlertDialog.Builder(this)
                .setPositiveButton("允许", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(@NonNull DialogInterface dialog, int which) {
                        request.proceed();
                    }
                })
                .setNegativeButton("拒绝", new DialogInterface.OnClickListener() {
                    @Override
                    public void onClick(@NonNull DialogInterface dialog, int which) {
                        request.cancel();
                    }
                })
                .setCancelable(false)
                .setMessage(messageResId)
                .show();
    }
}

3、附：危险权限和权限组列表

Android官方文档：https://developer.android.com/guide/topics/security/permissions.html#normal-dangerous

摘录如下：

权限组	权限
CALENDAR	READ_CALENDAR WRITE_CALENDAR
CAMERA	CAMERA
CONTACTS	READ_CONTACTS WRITE_CONTACTS GET_ACCOUNTS
LOCATION	ACCESS_FINE_LOCATION ACCESS_COARSE_LOCATION
PHONE	READ_PHONE_STATE CALL_PHONE READ_CALL_LOG WRITE_CALL_LOG ADD_VOICEMAIL USE_SIP PROCESS_OUTGOING_CALLS
SENSORS	BODY_SENSORS
SMS	SEND_SMS RECEIVE_SMS READ_SMS RECEIVE_WAP_PUSH RECEIVE_MMS
STORAGE	READ_EXTERNAL_STORAGE WRITE_EXTERNAL_STORAGE

4、附：Demo下载

http://download.csdn.net/detail/u012939909/9722890