Android API 23 Read_external_storage 权限问题

Question

我正在使用下面的代码。但是当我单击添加照片按钮时什么也没有发生。在 println 中，我看到了 4 号和 5 号。我做错了什么吗？我正在使用片段内的代码。任何帮助都会很棒。

int MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE;

// define in class
if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
    System.out.println("number 2");
    // We have access. Life is good.
} else if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), Manifest.permission.READ_EXTERNAL_STORAGE)) {
    System.out.println("number 3");
    // We've been denied once before. Explain why we need the permission, then ask again.
} else {
    System.out.println("number 4");
    // We've never asked. Just do it.
    ActivityCompat.requestPermissions(getActivity(), new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
    System.out.println("number 5");
}

回调部分如下：

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    if (requestCode == MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        // We got the permission

        System.out.println("number 6");

    } else {

        System.out.println("number 7");

        // We were not granted permission this time, so don't try to show the contact picker
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }
}

编辑：

我编辑我的代码如下，现在我在 println 日志中看到数字 4、5、7 和 8。没有错误，但什么都没有发生。不应该打开一个对话框要求用户授予权限吗？我使用带有 api 19 的 nexus 6 作为模拟器。

private static final int MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE = 7;
// define in class

if (ContextCompat.checkSelfPermission(getActivity(), Manifest.permission.READ_EXTERNAL_STORAGE) == PackageManager.PERMISSION_GRANTED) {
    System.out.println("number 2");
    // We have access. Life is good.
} else if (ActivityCompat.shouldShowRequestPermissionRationale(getActivity(), Manifest.permission.READ_EXTERNAL_STORAGE)) {
    System.out.println("number 3");
    // We've been denied once before. Explain why we need the permission, then ask again.
} else {
    System.out.println("number 4");
    // We've never asked. Just do it.
    requestPermissions(new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE);
    System.out.println("number 5");
}

回调部分如下：

@Override
public void onRequestPermissionsResult(int requestCode, String[] permissions, int[] grantResults) {
    if (requestCode == MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
        // We got the permission

        System.out.println("number 6");

    } else {

        System.out.println("number 7");

        // We were not granted permission this time, so don't try to show the contact picker
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);

        System.out.println("number 8");
    }
}

编辑 2：

我没有添加manifest的权限，我添加了<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />，现在看起来还可以。

Answer 1

MY_PERMISSIONS_REQUEST_READ_EXTERNAL_STORAGE 必须是具有值 to 的静态 int，以便检查多个权限并返回有效的比较结果。