我在Android m中写了一个权限请求的简写，这段代码还处理了对旧Android版本的向后兼容性。

所有丑陋的代码都被提取到一个片段中，该片段将自己附加到请求权限的活动上。PermissionRequestManager的使用方法如下:

new PermissionRequestManager()
        // We need a AppCompatActivity here, if you are not using support libraries you will have to slightly change 
        // the PermissionReuqestManager class
        .withActivity(this)

        // List all permissions you need
        .withPermissions(android.Manifest.permission.CALL_PHONE, android.Manifest.permission.READ_CALENDAR)

        // This Runnable is called whenever the request was successfull
        .withSuccessHandler(new Runnable() {
            @Override
            public void run() {
                // Do something with your permissions!
                // This is called after the user has granted all 
                // permissions, we are one a older platform where 
                // the user does not need to grant permissions 
                // manually, or all permissions are already granted

            }
        })

        // Optional, called when the user did not grant all permissions
        .withFailureHandler(new Runnable() {
            @Override
            public void run() {
                // This is called if the user has rejected one or all of the requested permissions
                L.e(this.getClass().getSimpleName(), "Unable to request permission");

            }
        })

        // After calling this, the user is prompted to grant the rights
        .request();

来看看:https://gist.github.com/crysxd/385b57d74045a8bd67c4110c34ab74aa

一个有用的函数来确定任意权限是否被阻止请求(在Kotlin中):

private fun isPermissionBlockedFromAsking(activity: Activity, permission: String): Boolean {
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.M) {
        return ContextCompat.checkSelfPermission(activity, permission) != PackageManager.PERMISSION_GRANTED
            && !activity.shouldShowRequestPermissionRationale(permission)
            && PreferenceManager.getDefaultSharedPreferences(activity).getBoolean(permission, false)
    }
    return false
}

当你第一次请求一个权限时，需要设置一个共享首选项布尔值为true，其中包含你想要的权限名称(例如android.Manifest.permission.READ_PHONE_STATE)。

解释:

Build.VERSION。SDK_INT >= Build.VERSION_CODES。因为有些代码只能在API级别23+上运行。

ContextCompat。checkSelfPermission(activity, permission) != PackageManager。permission_granting检查我们还没有权限。

activity.shouldShowRequestPermissionRationale(permission)来检查用户是否再次拒绝了应用程序的请求。由于这个函数的特性，还需要下面这行代码。

PreferenceManager.getDefaultSharedPreferences(活动)。getBoolean(permission, false)用于区分“Never asked”和“Never ask again”状态(以及在第一次权限请求时将值设置为true)，因为前一行不会返回此信息。

一旦用户标记了“不要再问”，该问题就不能再次显示。 但是可以向用户解释，他之前拒绝了权限，必须在设置中授予权限。并参考他的设置，使用以下代码:

@Override
public void onRequestPermissionsResult(int permsRequestCode, String[] permissions, int[] grantResults) {

    if (grantResults.length > 0
            && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        // now, you have permission go ahead
        // TODO: something

    } else {

        if (ActivityCompat.shouldShowRequestPermissionRationale(MainActivity.this,
                Manifest.permission.READ_CALL_LOG)) {
            // now, user has denied permission (but not permanently!)

        } else {

            // now, user has denied permission permanently!

            Snackbar snackbar = Snackbar.make(findViewById(android.R.id.content), "You have previously declined this permission.\n" +
                "You must approve this permission in \"Permissions\" in the app settings on your device.", Snackbar.LENGTH_LONG).setAction("Settings", new View.OnClickListener() {
            @Override
            public void onClick(View view) {

                startActivity(new Intent(android.provider.Settings.ACTION_APPLICATION_DETAILS_SETTINGS, Uri.parse("package:" + BuildConfig.APPLICATION_ID)));

            }
        });
        View snackbarView = snackbar.getView();
        TextView textView = (TextView) snackbarView.findViewById(android.support.design.R.id.snackbar_text);
        textView.setMaxLines(5);  //Or as much as you need
        snackbar.show();

        }

    }
    return;
}

开发者预览2对应用程序请求权限的方式进行了一些更改(参见http://developer.android.com/preview/support.html#preview2-notes)。

第一个对话框现在看起来像这样:

没有“永不再次显示”复选框(不像开发人员预览1)。如果用户拒绝权限，如果权限是必不可少的应用程序，它可以显示另一个对话框来解释应用程序请求该权限的原因，例如:

如果用户再次拒绝，应用程序应该关闭(如果它绝对需要该权限)或继续运行有限的功能。如果用户重新考虑(并选择重试)，则再次请求权限。这次的提示符是这样的:

第二次显示“永不再问”复选框。如果用户再次拒绝并且勾选复选框，就不会再发生任何事情。 是否勾选复选框可以通过使用Activity.shouldShowRequestPermissionRationale(String)来确定，例如:

if (shouldShowRequestPermissionRationale(Manifest.permission.WRITE_CONTACTS)) {...

这就是Android文档所说的(https://developer.android.com/training/permissions/requesting.html):

To help find the situations where you need to provide extra explanation, the system provides the Activity.shouldShowRequestPermissionRationale(String) method. This method returns true if the app has requested this permission previously and the user denied the request. That indicates that you should probably explain to the user why you need the permission. If the user turned down the permission request in the past and chose the Don't ask again option in the permission request system dialog, this method returns false. The method also returns false if the device policy prohibits the app from having that permission.

要知道用户是否拒绝了“never ask again”，你可以再次检查你的onRequestPermissionsResult中的shouldShowRequestPermissionRationale方法，当用户没有授予权限时。

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    if (requestCode == REQUEST_PERMISSION) {
        // for each permission check if the user granted/denied them
        // you may want to group the rationale in a single dialog,
        // this is just an example
        for (int i = 0, len = permissions.length; i < len; i++) {
            String permission = permissions[i];
            if (grantResults[i] == PackageManager.PERMISSION_DENIED) {
            // user rejected the permission
                boolean showRationale = shouldShowRequestPermissionRationale( permission );
                if (! showRationale) {
                    // user also CHECKED "never ask again"
                    // you can either enable some fall back,
                    // disable features of your app
                    // or open another dialog explaining
                    // again the permission and directing to
                    // the app setting
                } else if (Manifest.permission.WRITE_CONTACTS.equals(permission)) {
                    showRationale(permission, R.string.permission_denied_contacts);
                    // user did NOT check "never ask again"
                    // this is a good place to explain the user
                    // why you need the permission and ask if he wants
                    // to accept it (the rationale)
                } else if ( /* possibly check more permissions...*/ ) {
                }
            }
        }
    }
}

你可以用下面的代码打开你的应用程序设置:

Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
Uri uri = Uri.fromParts("package", getPackageName(), null);
intent.setData(uri);
startActivityForResult(intent, REQUEST_PERMISSION_SETTING);

无法将用户直接发送到授权页面。

OnRequestPermissionResult-free和shouldshowrequestpermissionrationalfree方法:

public static void requestDangerousPermission(AppCompatActivity activity, String permission) {
        if (hasPermission(activity, permission)) return;
        requestPermission();

        new Handler().postDelayed(() -> {
            if (activity.getLifecycle().getCurrentState() == Lifecycle.State.RESUMED) {
                Intent intent = new Intent(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                intent.setData(Uri.parse("package:" + context.getPackageName()));
                context.startActivity(intent);
            }
        }, 250);
    }

如果没有权限弹出，250ms后打开设备设置(如果选择了“Never ask again”，就是这种情况)。

你可以在onRequestPermissionsResult()中检查shouldShowRequestPermissionRationale()。

https://youtu.be/C8lUdPVSzDk?t=2m23s

在onRequestPermissionsResult()中检查权限是否被授予。如果不是，检查shouldShowRequestPermissionRationale()。

如果此方法返回true，则说明为什么需要此特定权限。然后根据用户的选择再次请求permissions()。 如果它返回false，则显示一个错误消息，权限未授予，应用程序不能继续前进或特定功能被禁用。

下面是示例代码。

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    switch (requestCode) {
        case STORAGE_PERMISSION_REQUEST:
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                // permission was granted :)
                downloadFile();
            } else {
                // permission was not granted
                if (getActivity() == null) {
                    return;
                }
                if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), Manifest.permission.WRITE_EXTERNAL_STORAGE)) {
                    showStoragePermissionRationale();
                } else {
                    Snackbar snackbar = Snackbar.make(getView(), getResources().getString(R.string.message_no_storage_permission_snackbar), Snackbar.LENGTH_LONG);
                    snackbar.setAction(getResources().getString(R.string.settings), new View.OnClickListener() {
                        @Override
                        public void onClick(View v) {
                            if (getActivity() == null) {
                                return;
                            }
                            Intent intent = new Intent();
                            intent.setAction(Settings.ACTION_APPLICATION_DETAILS_SETTINGS);
                            Uri uri = Uri.fromParts("package", getActivity().getPackageName(), null);
                            intent.setData(uri);
                            OrderDetailFragment.this.startActivity(intent);
                        }
                    });
                    snackbar.show();
                }
            }
            break;
    }
}

显然，谷歌maps对位置许可正是这样做的。