Question

我正在学习如何申请权限。现在我想使用相机硬件，我正在尝试请求此权限。我提到了Android开发者的官方网站，我使用了网站上发布的示例我改变了一点，因为我需要Android Camera硬件。

清单文件不包含任何权限，我希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。但是发生的事情是，当我运行App时它没有问添加任何权限，也不会显示“Toast”。

请向我解释为什么会发生这种情况以及如何正确设置

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

使用以下代码打开对话框：

 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

您正尝试在else部分中请求权限...即已授予权限时。

外部其他表示授予权限....请执行以下操作

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
}

所以正确的代码如下所示：

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

您是否在Android m设备中运行该应用程序？

仅在android marshmallow设备中询问权限以获取更多信息请参阅here

对于在较低版本中运行的其他Android设备，其他marshmallow你需要在android manefest中声明权限......

请注意，权限对话框不会出现在运行低于android-m

的版本的Android设备中

Answer 5

private boolean checkWriteExternalPermission（） {

part = "Hi! Goodmorning, I'm fine."
list = [[H,i],[!],[_],[G,o,o,d,m,o,r,n,i,n,g],[,],[_],[I],['],[m],[_],[f,i,n,e],[.]]

}

How permission can be checked at runtime without throwing SecurityException?

Answer 6

即使您尝试为Android M实施运行时权限模型，也需要在AndroidManifest.xml中列出这些权限。

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

然后在用户操作后：

    @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;

    }
}

未获得请求权限

6 个答案: