java - Android 7.0 运行时权限检查

Question

当我尝试在 sdcard 中创建文件时:

newFile.createNewFile();

我得到的日志如下:

W/System.err: java.io.IOException: Permission denied

W/System.err: at java.io.UnixFileSystem.createFileExclusively0(Native Method)

W/System.err: at java.io.UnixFileSystem.createFileExclusively(UnixFileSystem.java:280)

W/System.err: at java.io.File.createNewFile(File.java:948)

我知道原因是未授予危险的运行时权限 (WRITE_EXTERNAL_STORAGE)，但是当我尝试在 PackageManagerService.java checkUidPermission() 中打印日志时，发现它没有被调用。

我想知道native method(比如java.io.UnixFileSystem.createFileExclusively0)是怎么判断runtime Permission没有被授予的？

Answer 1

从 Android M 开始，用户可以在运行时而非安装时授予/撤销权限。

因此，当针对具有 M 及更高版本的设备时，您需要检查权限是否被授予我使用此类来检查权限我希望它有所帮助:

/**
 * Created by Mani on 17/09/16.
 * Making the runtime app permissions for android marshmallow+ devices cleaner
 * Specify all the requests here
 */
public class MarshMallowPermission {
    private static final int CALL_PERMISSION_REQUEST_CODE = 1;
    public static final int EXTERNAL_STORAGE_PERMISSION_REQUEST_CODE = 2;
    public static final int CAMERA_PERMISSION_REQUEST_CODE = 3;
    public static final int SHORT_CUT_PERMISSION_REQUEST_CODE = 4;
    private Activity activity;


    public MarshMallowPermission(Activity activity) {
        this.activity = activity;
    }

    public boolean checkPermissionForCall(){
        int result = ContextCompat.checkSelfPermission(activity, Manifest.permission.CALL_PHONE);
        return result == PackageManager.PERMISSION_GRANTED;
    }

    @RequiresApi(api = Build.VERSION_CODES.KITKAT)
    public boolean checkPermissionForShortCut(){


        int result = PermissionChecker.checkSelfPermission(activity,Manifest.permission.INSTALL_SHORTCUT);
        return result == PermissionChecker.PERMISSION_GRANTED;
    }


    public boolean checkPermissionForExternalStorage(){
        int result = ContextCompat.checkSelfPermission(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE);
        int readStorage = 0;
        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
            readStorage = ContextCompat.checkSelfPermission(activity, Manifest.permission.READ_EXTERNAL_STORAGE);
        }

        return result == PackageManager.PERMISSION_GRANTED && readStorage == PackageManager.PERMISSION_GRANTED;
    }

    public boolean checkPermissionForCamera(){
        int result = ContextCompat.checkSelfPermission(activity, Manifest.permission.CAMERA);
        return result == PackageManager.PERMISSION_GRANTED;
    }


    public void requestPermissionForCall(){
        if (ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.CALL_PHONE)){
            Toast.makeText(activity, "Call Phone Permission required to launch Dialer. Please allow in App Settings for additional functionality.", Toast.LENGTH_LONG).show();
        } else {
            ActivityCompat.requestPermissions(activity,new String[]{Manifest.permission.CALL_PHONE},CALL_PERMISSION_REQUEST_CODE);
        }
    }

    public void requestPermissionForExternalStorage(){
        if (ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.WRITE_EXTERNAL_STORAGE)){
            Toast.makeText(activity, "External Storage permission required. Please allow in App Settings for additional functionality.", Toast.LENGTH_LONG).show();
        } else {
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                ActivityCompat.requestPermissions(activity,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE,Manifest.permission.READ_EXTERNAL_STORAGE},EXTERNAL_STORAGE_PERMISSION_REQUEST_CODE);
            }else{
                ActivityCompat.requestPermissions(activity,new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE},EXTERNAL_STORAGE_PERMISSION_REQUEST_CODE);
            }
        }
    }

    public void requestPermissionForCamera(){
        if (ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.CAMERA)){
            Toast.makeText(activity, "Camera permission required. Please allow in App Settings for additional functionality.", Toast.LENGTH_LONG).show();
        } else {
            ActivityCompat.requestPermissions(activity,new String[]{Manifest.permission.CAMERA},CAMERA_PERMISSION_REQUEST_CODE);
        }
    }

    public void requestPermissionForShortCut(){
        if (ActivityCompat.shouldShowRequestPermissionRationale(activity, Manifest.permission.INSTALL_SHORTCUT)){
            Toast.makeText(activity, "Create ShortCut permission required. Please allow in App Settings for additional functionality.", Toast.LENGTH_LONG).show();
        } else {
            ActivityCompat.requestPermissions(activity,new String[]{Manifest.permission.INSTALL_SHORTCUT},SHORT_CUT_PERMISSION_REQUEST_CODE);
        }
    }
}

在 Activity 中使用:

MarshMallowPermission marshMallowPermission = new MarshMallowPermission(MyActivity.this);

marshMallowPermission.checkPermissionForCall();

marshMallowPermission.requestPermissionForCall();

如果您有任何疑问，请在下方评论。