可以向我解释一下我应该如何向用户许可解释

我使用 Camera2API 并实现了这样的代码 fragment 来动态询问 permishion

private void openCamera(int width, int height) {
    setUpCameraOutputs(width, height);
    CameraHelper.configureTransform(width, height, textureView, previewSize, getActivity());
    CameraManager manager = (CameraManager) getSystemService(Context.CAMERA_SERVICE);

    try {
        if (!cameraOpenCloseLock.tryAcquire(2500, TimeUnit.MILLISECONDS)) {
            throw new RuntimeException("Time out waiting to lock camera opening.");
        }

        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) !=
                PackageManager.PERMISSION_GRANTED) {

            // Should we show an explanation?
            if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {

                // Show an explanation to the user *asynchronously* -- don't block
                // this thread waiting for the user's response! After the user
                // sees the explanation, try again to request the permission.

            } else {
                // No explanation needed, we can request the permission.

                ActivityCompat.requestPermissions(
                        getActivity(), new String[]{android.Manifest.permission.CAMERA},
                        MY_PERMISSIONS_REQUEST);

                // MY_PERMISSIONS_REQUEST is an
                // app-defined int constant. The callback method gets the
                // result of the request.
            }
        }

        manager.openCamera(mCameraId, mStateCallback, mBackgroundHandler);
    } catch (CameraAccessException e) {
        e.printStackTrace();
    } catch (InterruptedException e) {
        throw new RuntimeException("Interrupted while trying to lock camera opening.", e);
    }
}

根据 google docks，我应该先检查用户是否拒绝许可

有返回真或假的方法

shouldShowRequestPermissionRationale();

根据谷歌

This method returns true if the app has requested this permission previously and the user denied the request.

如果我根据此方法实现中的谷歌评论正确理解

// Show an explanation to the user asynchronously -- don't block

// this thread waiting for the user's response! After the user

// sees the explanation, try again to request the permission.

最后，例如用户在使用相机应用程序进入我的屏幕之前和下次拒绝我的许可应该创建我的 castom 弹出窗口并解释“如果您想继续，请同意此权限”，例如用户同意这次我应该根据这个再次记忆这个方法

// sees the explanation, try again to request the permission.

但是这个方法

shouldShowRequestPermissionRationale();

再次返回给我 true，因为它不知道用户同意许可的 Intent 。

你能解释一下如何正确地制作它吗？也许你有例子？

最佳答案

最终我在@nuuneoi 的帮助下找到了解决方案，非常感谢!

然后这样实现

public void camera(View view) {
    toCamera();
}

private void toCamera() {
    if (!isCheckPermission()){
        return;
    }

    if (isProcessWasFinish()) {
        startActivity(new Intent(getApplicationContext(), CameraActivity.class));
        overridePendingTransition(R.anim.open_next, R.anim.close_main);
    } else {
        startActivity(new Intent(getApplicationContext(), UserDataScreen.class));
        overridePendingTransition(R.anim.open_next, R.anim.close_main);
    }
}

private boolean isCheckPermission() {
    if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) !=
            PackageManager.PERMISSION_GRANTED) {

        // Should we show an explanation?
        if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
            showMessageOKCancel("You need to allow access to Camera");
            return false;
        }

        // No explanation needed, we can request the permission.

        ActivityCompat.requestPermissions(this, new String[]{android.Manifest.permission.CAMERA},
                MY_PERMISSIONS_REQUEST);
        return false;
        // MY_PERMISSIONS_REQUEST is an
        // app-defined int constant. The callback method gets the
        // result of the request.
    }

    return true;
}

private void showMessageOKCancel(String message) {
    new AlertDialog.Builder(MainActivity.this)
            .setMessage(message)
            .setPositiveButton("OK", listener)
            .setNegativeButton("Cancel", listener)
            .create()
            .show();
}

DialogInterface.OnClickListener listener = new DialogInterface.OnClickListener() {

    final int BUTTON_NEGATIVE = -2;
    final int BUTTON_POSITIVE = -1;

    @Override
    public void onClick(DialogInterface dialog, int which) {
        switch (which) {
            case BUTTON_NEGATIVE:
                // int which = -2
                dialog.dismiss();
                break;

            case BUTTON_POSITIVE:
                // int which = -1
                ActivityCompat.requestPermissions(
                        MainActivity.this, new String[]{android.Manifest.permission.CAMERA},
                        MY_PERMISSIONS_REQUEST);
                dialog.dismiss();
                break;
        }
    }
};

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions,
                                       @NonNull int[] grantResults) {
    switch (requestCode) {
        case MY_PERMISSIONS_REQUEST: {
            // If request is cancelled, the result arrays are empty.
            if (grantResults.length > 0
                    && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                Log.e(MY_LOG, "Camera permission Granted");
                // permission was granted, yay! Do the
                // contacts-related task you need to do.

                toCamera();

            } else {
                Log.e(MY_LOG, "Camera permission Denied");
                // permission denied, boo! Disable the
                // functionality that depends on this permission.
            }
        }
        default: {
            super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        }

        // other 'case' lines to check for other
        // permissions this app might request
    }
}

关于java - 棉花糖权限及说明，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/38072363/