允许使用照相机[副本]

Question

为什么应用程序在安装过程中不请求使用摄像头的许可？

舱单：

<uses-feature android:name="android.hardware.camera"
    android:required="true"/>

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.INTERNET" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />

Answer 1

权限有两种类型。

1. 正常权限（不需要向用户询问）
2. 危险权限（需要询问）

在你的清单中有三个危险的许可。

<uses-permission android:name="android.permission.ACCESS_NETWORK_STATE" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.CAMERA" />

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

@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", Toast.LENGTH_SHORT).show();
            }
            return;
        }

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

提示：

如果您不想为请求不同类中的权限编写太多代码。用一些图书馆。像

• https://github.com/tbruyelle/rxpermissions
• https://github.com/karumi/dexter

rxPermissions
    .request(Manifest.permission.CAMERA)
    .subscribe(granted -> {
        if (granted) { // Always true pre-M
           // I can control the camera now
        } else {
           // Oups permission denied
        }
    });