Foreword

之前总是有小伙伴问 AndroidUtilCode 中有没有权限工具类，但都被我怼回去了，让先用着其他第三方的，不过，到了如今的 1.11.0 版本的 AndroidUtilCode，这个一直拖欠着的权限工具类总算要问世了，以后小伙伴们如果用 AndroidUtilCode 需要动态授权的话，就不用再多依赖一个第三方库了，下面来介绍下其功能。

Functions

• 兼容安卓各版本，包括 Android 8.0
• 支持任意地方申请权限，不仅限于 Activity 和 Fragment 等
• 支持多权限同时申请
• 采用链式调用，一句话解决权限申请

Achieve

首先来介绍其实现方式，关于运行时权限的介绍可以在官网查看 -> 传送门。关于危险权限列表，我封装危险权限常量类 PermissionConstants.java，代码如下所示：

import android.Manifest;
import android.Manifest.permission;
import android.annotation.SuppressLint;
import android.support.annotation.StringDef;

import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;


/**
 * <pre>
 *     author: Blankj
 *     blog  : http://blankj.com
 *     time  : 2017/12/29
 *     desc  : 权限相关常量
 * </pre>
 */
@SuppressLint("InlinedApi")
public final class PermissionConstants {

    public static final String CALENDAR   = Manifest.permission_group.CALENDAR;
    public static final String CAMERA     = Manifest.permission_group.CAMERA;
    public static final String CONTACTS   = Manifest.permission_group.CONTACTS;
    public static final String LOCATION   = Manifest.permission_group.LOCATION;
    public static final String MICROPHONE = Manifest.permission_group.MICROPHONE;
    public static final String PHONE      = Manifest.permission_group.PHONE;
    public static final String SENSORS    = Manifest.permission_group.SENSORS;
    public static final String SMS        = Manifest.permission_group.SMS;
    public static final String STORAGE    = Manifest.permission_group.STORAGE;

    private static final String[] GROUP_CALENDAR   = {
            permission.READ_CALENDAR, permission.WRITE_CALENDAR
    };
    private static final String[] GROUP_CAMERA     = {
            permission.CAMERA
    };
    private static final String[] GROUP_CONTACTS   = {
            permission.READ_CONTACTS, permission.WRITE_CONTACTS, permission.GET_ACCOUNTS
    };
    private static final String[] GROUP_LOCATION   = {
            permission.ACCESS_FINE_LOCATION, permission.ACCESS_COARSE_LOCATION
    };
    private static final String[] GROUP_MICROPHONE = {
            permission.RECORD_AUDIO
    };
    private static final String[] GROUP_PHONE      = {
            permission.READ_PHONE_STATE, permission.READ_PHONE_NUMBERS, permission.CALL_PHONE,
            permission.ANSWER_PHONE_CALLS, permission.READ_CALL_LOG, permission.WRITE_CALL_LOG,
            permission.ADD_VOICEMAIL, permission.USE_SIP, permission.PROCESS_OUTGOING_CALLS
    };
    private static final String[] GROUP_SENSORS    = {
            permission.BODY_SENSORS
    };
    private static final String[] GROUP_SMS        = {
            permission.SEND_SMS, permission.RECEIVE_SMS, permission.READ_SMS,
            permission.RECEIVE_WAP_PUSH, permission.RECEIVE_MMS,
    };
    private static final String[] GROUP_STORAGE    = {
            permission.READ_EXTERNAL_STORAGE, permission.WRITE_EXTERNAL_STORAGE
    };

    @StringDef({CALENDAR, CAMERA, CONTACTS, LOCATION, MICROPHONE, PHONE, SENSORS, SMS, STORAGE,})
    @Retention(RetentionPolicy.SOURCE)
    public @interface Permission {
    }

    public static String[] getPermissions(@Permission final String permission) {
        switch (permission) {
            case CALENDAR:
                return GROUP_CALENDAR;
            case CAMERA:
                return GROUP_CAMERA;
            case CONTACTS:
                return GROUP_CONTACTS;
            case LOCATION:
                return GROUP_LOCATION;
            case MICROPHONE:
                return GROUP_MICROPHONE;
            case PHONE:
                return GROUP_PHONE;
            case SENSORS:
                return GROUP_SENSORS;
            case SMS:
                return GROUP_SMS;
            case STORAGE:
                return GROUP_STORAGE;
        }
        return new String[]{permission};
    }
}复制代码

为了适配 Android 8.0，我在申请权限的时候，会把清单文件中使用到的同组的权限都一次性申请完毕，相关代码如下所示：

private static final List<String> PERMISSIONS = getPermissions();

/**
 * 获取应用权限
 *
 * @return 清单文件中的权限列表
 */
public static List<String> getPermissions() {
    return getPermissions(Utils.getApp().getPackageName());
}

/**
 * 获取应用权限
 *
 * @param packageName 包名
 * @return 清单文件中的权限列表
 */
public static List<String> getPermissions(final String packageName) {
    PackageManager pm = Utils.getApp().getPackageManager();
    try {
        return Arrays.asList(
                pm.getPackageInfo(packageName, PackageManager.GET_PERMISSIONS)
                        .requestedPermissions
        );
    } catch (PackageManager.NameNotFoundException e) {
        e.printStackTrace();
        return Collections.emptyList();
    }
}

/**
 * 设置请求权限
 *
 * @param permissions 要请求的权限
 * @return {@link PermissionUtils}
 */
public static PermissionUtils permission(@Permission final String... permissions) {
    return new PermissionUtils(permissions);
}

private PermissionUtils(final String... permissions) {
    mPermissions = new LinkedHashSet<>();
    for (String permission : permissions) {
        for (String aPermission : PermissionConstants.getPermissions(permission)) {
            if (PERMISSIONS.contains(aPermission)) {
                mPermissions.add(aPermission);
            }
        }
    }
    sInstance = this;
}复制代码

为了支持任意地方都可以申请权限，我在 PermissionUtils.java 中封装了 PermissionActivity，源码如下所示：

@RequiresApi(api = Build.VERSION_CODES.M)
public static class PermissionActivity extends Activity {
    public static void start(final Context context) {
        Intent starter = new Intent(context, PermissionActivity.class);
        starter.addFlags(Intent.FLAG_ACTIVITY_NEW_TASK);
        context.startActivity(starter);
    }
    @Override
    protected void onCreate(@Nullable Bundle savedInstanceState) {
        if (sInstance.mThemeCallback != null) {
            sInstance.mThemeCallback.onActivityCreate(this);
        } else {
            Window window = getWindow();
            window.setBackgroundDrawable(null);
            int option = View.SYSTEM_UI_FLAG_LAYOUT_STABLE
                    | View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN;
            window.getDecorView().setSystemUiVisibility(option);
            window.setStatusBarColor(Color.TRANSPARENT);
        }
        super.onCreate(savedInstanceState);
        if (sInstance.rationale(this)) {
            finish();
            return;
        }
        if (sInstance.mPermissionsRequest != null) {
            int size = sInstance.mPermissionsRequest.size();
            requestPermissions(sInstance.mPermissionsRequest.toArray(new String[size]), 1);
        }
    }
    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           @NonNull String[] permissions,
                                           @NonNull int[] grantResults) {
        sInstance.onRequestPermissionsResult(this);
        finish();
    }
}复制代码

这样我们便可以自己全权处理权限请求，但启动的这个 PermissionActivity 的主题并不一定符合小伙伴们应用的 Activity 相关主题，所以我留了个设置主题的回调接口，比如可以把这个 Activity 设置为全屏等操作，这样便可无感知地启动一个 Activity，相关主题属性如下：

<style name="ActivityTranslucent">
    <item name="android:windowBackground">@android:color/transparent</item>
    <item name="android:colorBackgroundCacheHint">@null</item>
    <item name="android:windowIsTranslucent">true</item>
    <item name="android:windowNoTitle">true</item>
    <item name="android:windowContentOverlay">@null</item>
    <item name="android:activityOpenEnterAnimation">@null</item>
    <item name="android:activityOpenExitAnimation">@null</item>
    <item name="android:activityCloseEnterAnimation">@null</item>
    <item name="android:activityCloseExitAnimation">@null</item>
    <item name="android:statusBarColor">@android:color/transparent</item>
</style>复制代码

这个应该能适配很多应用了。

当然，如果有设置 rationale 的话，也就是设置拒绝权限后再次请求的回调接口，此时便会走 sInstance.rationale(this)，具体代码如下所示：

@RequiresApi(api = Build.VERSION_CODES.M)
private boolean rationale(final Activity activity) {
    boolean isRationale = false;
    if (mOnRationaleListener != null) {
        for (String permission : mPermissionsRequest) {
            if (activity.shouldShowRequestPermissionRationale(permission)) {
                getPermissionsStatus(activity);
                mOnRationaleListener.rationale(new ShouldRequest() {
                    @Override
                    public void again(boolean again) {
                        if (again) {
                            startPermissionActivity();
                        } else {
                            requestCallback();
                        }
                    }
                });
                isRationale = true;
                break;
            }
        }
        mOnRationaleListener = null;
    }
    return isRationale;
}复制代码

逻辑就是如果 rationale 回调接口 执行了 shouldRequest.again(true);，那么就会继续申请下去，反之则不再申请，多用在弹出一个提示对话框来让用户选择是否继续请求权限。

最终就是发起请求和接受请求，并把最终状态保存到 mPermissionsGranted、mPermissionsDenied 和 mPermissionsDeniedForever 中，最终回调 callback 的接口，相关代码如下所示：

private void getPermissionsStatus(final Activity activity) {
    for (String permission : mPermissionsRequest) {
        if (isGranted(permission)) {
            mPermissionsGranted.add(permission);
        } else {
            mPermissionsDenied.add(permission);
            if (!activity.shouldShowRequestPermissionRationale(permission)) {
                mPermissionsDeniedForever.add(permission);
            }
        }
    }
}

private void requestCallback() {
    if (mSimpleCallback != null) {
        if (mPermissionsRequest.size() == 0
                || mPermissions.size() == mPermissionsGranted.size()) {
            mSimpleCallback.onGranted();
        } else {
            if (!mPermissionsDenied.isEmpty()) {
                mSimpleCallback.onDenied();
            }
        }
        mSimpleCallback = null;
    }
    if (mFullCallback != null) {
        if (mPermissionsRequest.size() == 0
                || mPermissions.size() == mPermissionsGranted.size()) {
            mFullCallback.onGranted(mPermissionsGranted);
        } else {
            if (!mPermissionsDenied.isEmpty()) {
                mFullCallback.onDenied(mPermissionsDeniedForever, mPermissionsDenied);
            }
        }
        mFullCallback = null;
    }
    mOnRationaleListener = null;
    mThemeCallback = null;
}

private void onRequestPermissionsResult(final Activity activity) {
    getPermissionsStatus(activity);
    requestCallback();
}复制代码

说了那么多，总算到使用了，其实使用起来非常方便，一句话即可，比如我们要申请 android.permission.READ_CALENDAR 权限，那么我们可以去 PermissionConstants.java 中找到其所属组，也就是 CALENDAR，而应用是全屏类型的应用，那么我们可以像下面这样发起请求。

PermissionUtils.permission(PermissionConstants.CALENDAR)
        .rationale(new PermissionUtils.OnRationaleListener() {
            @Override
            public void rationale(final ShouldRequest shouldRequest) {
                PermissionHelper.showRationaleDialog(shouldRequest);
            }
        })
        .callback(new PermissionUtils.FullCallback() {
            @Override
            public void onGranted(List<String> permissionsGranted) {
                updateAboutPermission();
            }
            @Override
            public void onDenied(List<String> permissionsDeniedForever,
                                 List<String> permissionsDenied) {
                if (!permissionsDeniedForever.isEmpty()) {
                    PermissionHelper.showOpenAppSettingDialog();
                }
                LogUtils.d(permissionsDeniedForever, permissionsDenied);
            }
        })
        .theme(new PermissionUtils.ThemeCallback() {
            @Override
            public void onActivityCreate(Activity activity) {
                ScreenUtils.setFullScreen(activity);
            }
        })
        .request();复制代码

如果还有不会的可以参考 AndroidUtilCode 中的 demo -> PermissionActivity.java

Tips：推荐小伙伴们最好把权限请求相关的操作都放在一个 helper 类中，就像我 AndroidUtilCode 中 demo 的做法，创建一个 PermissionHelper.java，毕竟有很多权限请求都是重复。

Conclusion

好了，本次的权限工具类介绍就到此结束了，在这么简洁的工具类背后都是本柯基辛勤付出的汗水，疯狂地 debug，疯狂地测试来消除内存泄漏的问题，虽然路途很艰辛，但最终还是成功地完成了该工具类，终于等到你。