权限未得到请求

Question

我正在学习如何请求权限。现在我想使用相机硬件，并且我正在尝试请求此权限。我提到Android开发人员的官方网站，我用网站上发布的例子，但 我改变了一点，因为我需要Android Camera硬件。

清单文件不包含任何权限，我期望当我运行以下发布的代码时，“Toast”将显示，因为清单文件中没有添加任何权限。但是发生的是，当我运行应用程序时，它不会要求 添加任何权限，也不会显示“Toast”。

这是为什么happeneing请向我解释，以及如何设置正确

代码：使用下面的代码

int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA); 
if (permissionCheck != PackageManager.PERMISSION_GRANTED) { 

    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) { 
     Toast.makeText(this, "permission is not in the manifest file", Toast.LENGTH_SHORT).show(); 
    } 

} else { 
    ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, MY_PERMISSIONS_REQUEST_CAMERA); 
} 

Answer 1

打开一个对话框：

ActivityCompat.requestPermissions(MainActivity.this, 
        new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 
        1); 

获取活动结果如下：

@Override 
public void onRequestPermissionsResult(int requestCode, 
             String permissions[], int[] grantResults) { 
    switch (requestCode) { 
     case 1: { 

      // If request is cancelled, the result arrays are empty. 
      if (grantResults.length > 0 
        && grantResults[0] == PackageManager.PERMISSION_GRANTED) { 

       // permission was granted, yay! Do the 
       // contacts-related task you need to do.   
      } else { 

       // permission denied, boo! Disable the 
       // functionality that depends on this permission. 
       Toast.makeText(MainActivity.this, "Permission denied to read your External storage", Toast.LENGTH_SHORT).show(); 
      } 
      return; 
     } 

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

更多信息：https://developer.android.com/training/permissions/requesting.html

Answer 2

您正试图请求权限的其他部分...即权限已被授予。

外其他意味着权限被授予....做，而不是下面

int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA); 
if (permissionCheck != PackageManager.PERMISSION_GRANTED) { 

    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) { 
     Toast.makeText(this, "permission is not in the manifest file", Toast.LENGTH_SHORT).show(); 
    } else{ 
      ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, MY_PERMISSIONS_REQUEST_CAMERA); 
    } 

} else { 
    Toast.makeText(this, "permission is granted already", Toast.LENGTH_SHORT).show(); 
} 

Answer 3

if (permissionCheck != PackageManager.PERMISSION_GRANTED) { 
// here you need to request permission, or show explanation if needed 
} else { 
//we already have permission, no need to request 
} 

所以正确的代码应该是这样的：

int permissionCheck = ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA); 
if (permissionCheck != PackageManager.PERMISSION_GRANTED) { 

    if (ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) { 
     Toast.makeText(this, "permission is not in the manifest file", Toast.LENGTH_SHORT).show(); 
    } else { 
     ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.CAMERA}, MY_PERMISSIONS_REQUEST_CAMERA); 
    } 
} 

Answer 4

你运行android m设备中的应用程序？

的权限要求只有在获得更多信息的Android设备棉花糖请参考here

对于其他的是棉花糖u需要在Android的manefest声明权限较低的版本上运行其他Android设备......

请注意，权限对话框不会出现在运行低于android-m的android设备上

Answer 5

private boolean checkWriteExternalPermission（） {

String permission = "android.permission.WRITE_EXTERNAL_STORAGE"; 
int res = getContext().checkCallingOrSelfPermission(permission); 
return (res == PackageManager.PERMISSION_GRANTED);    

}

How permission can be checked at runtime without throwing SecurityException?

Answer 6

你必须在AndroidManifest.xml中列出的权限，即使你想实现的Android M.运行权限模型

if(ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA)==PackageManager.PERMISSION_GRANTED){ 
     //do something 
    } 
    else 
     requestPermissions(permissionsList, 
       MY_PERMISSIONS_REQUEST_CODE); 

然后用户操作后：

@Override 
public void onRequestPermissionsResult(int requestCode, 
             String permissions[], int[] grantResults) { 
    switch (requestCode) { 
     case MY_PERMISSIONS_REQUEST_CODE: 
      if (grantResults[0] == PackageManager.PERMISSION_GRANTED) { 
       //do something 
      } else{ 
       //do some other thing 
      } 
      break; 

    } 
}