Question

我正在尝试开发一款在Android中使用相机硬件的应用。编码以下行

this.mCameraManager.openCamera(cameraIds[0], new CameraDevice.StateCallback() {...}

我被要求明确检查是否有权限。当我添加权限检查时，Android添加了以下行

if (ActivityCompat.checkSelfPermission(this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
            // TODO: Consider calling
            //    ActivityCompat#requestPermissions
            // here to request the missing permissions, and then overriding
            //   public void onRequestPermissionsResult(int requestCode, String[] permissions,
            //                                          int[] grantResults)
            // to handle the case where the user grants the permission. See the documentation
            // for ActivityCompat#requestPermissions for more details.
            return;
        }

我重写了以下方法

@Override
public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
    super.onRequestPermissionsResult(requestCode, permissions, grantResults);
}

现在，我不知道在if语句和上面提到的“onRequestPermissionsResult”中写什么。非常感谢您的帮助

Answer 1

// Can define this wherever
Response.Listener<JSONObject> dataListener = new Response.Listener<JSONObject>() {
    @Override
    public void onResponse(JSONObject response) {
        Weather weather = getJsonWeatherData(response);
        setWeatherobj(weather);
  }
};

// This error listener is almost always the same, anyway, right?
Response.ErrorListener errorListener = new Response.ErrorListener() {
    @Override
    public void onErrorResponse(VolleyError error) {
        Log.i("Error","can't process json result");
    }
}

JsonObjectRequest jsonObjectRequest=new JsonObjectRequest(Request.Method.GET, url, 
    null, // Data
    dataListener, // onSuccess
    errorListener // onError
);

MySingleton.getInstance(getApplicationContext())
    .addToRequestQue(jsonObjectRequest); // Some RequestQueue

您必须向用户显示Android权限对话框，之后您可以在onRequestPermissionsResult中捕获用户动作。

我认为你应该看看这个网站：https://developer.android.com/training/permissions/requesting.html

Answer 2

 @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case REQUEST_CODE_PERMISSIONS:
                if (grantResults.length > 0
                        && grantResults[0] == PackageManager.PERMISSION_GRANTED)
                   // Open Camera
                break;
        }
    }

Answer 3

试试这个：

// The permission required by the application to work properly
    protected static final String[] requiredPermissions;
    private static final int PERMISSION_REQUEST = 0;

    static {
        List<String> perms = new ArrayList<>(Arrays.asList(
                Manifest.permission.WRITE_EXTERNAL_STORAGE,
                Manifest.permission.CAMERA,
                Manifest.permission.RECORD_AUDIO
        ));
        requiredPermissions = perms.toArray(new String[perms.size()]);
    }

在onCreate（）中调用verifyPermissions（）方法：

private void verifyPermissions() {
        if (!hasAllPermissions()) {
            // We don't have permission so prompt the user
            ActivityCompat.requestPermissions(
                    this,
                    requiredPermissions,
                    PERMISSION_REQUEST
            );
        }
    }

    private boolean hasAllPermissions() {
        // Check if we have all required permissions.
        for (String perm : requiredPermissions) {
            if (ActivityCompat.checkSelfPermission(this, perm) != PackageManager.PERMISSION_GRANTED) {
                return false;
            }
        }
        return true;
    }

    @Override
    public void onRequestPermissionsResult(int requestCode,
                                           String permissions[], int[] grantResults) {
        switch (requestCode) {
            case PERMISSION_REQUEST: {
                // If request is cancelled, the result arrays are empty.
                if (!hasAllPermissions()) {
                    finish();
                }
                return;
            }
        }
    }

如何申请打开相机硬件的权限

3 个答案: