安卓6.0动态获取多个权限

本文的应用场景是打开摄像头页面扫描二维码并需要定位权限（6.0及以上的系统获取wif列表需要打开GPS）,涉及多个权限的申请逻辑。

先讲一讲需要注意的问题：

1.摄像头使用SurfaceView,会出现处理权限弹窗后，摄像头黑屏，或从后台进入前台时黑屏，原因是SurfaceView绑定Callback的时机不对，导致SurfaceHolder.callBack没有执行，解决方法是将绑定的时机放在onResume函数中。

 @Override
    public void onResume() {
        super.onResume();
        initViews();
        inactivityTimer.onResume();
    }
 private void initViews() {
        //  autoFocusHandler = new Handler();
        cameraManager = new CameraManager(getApplication());
        handler = null;
        scanPreview.getHolder().addCallback(this);
        startLineAnimation();
    }

2.需要获取拍照权限及GPS定位权限（在先申请的权限的onRequestPermissionsResult回调里申请第二个权限，权限检测的if-else逻辑也需要处理好，不重复检测也不漏检测）

具体实现：在摄像头SurfaceHolder.Callback回调中检测GPS定位权限、拍照权限是否已经有，调用如下函数：

RequestPermission（）:判断是否有定位权限，没有定位权限则申请定位权限，若有则判断有拍照权限否，没有就申请拍照权限，若都有则进行摄像头的初始化准备工作。

private SurfaceHolder.Callback mCallback = new SurfaceHolder.Callback(){
   @Overrride
   public void surfaceCreated(SurfaceHolder holder){
     RequestPermission();
   }
   @Override
   public void surfaceChanged(SurfaceHoldeer holder, int format, int width, int height){
   
   }
   @Override
   public void surfaceDestoryed(SurfaceHolder holder){
   
   }

};

private void RequestPermission() {
        if (Build.VERSION.SDK_INT >= 23) {

            if (ContextCompat.checkSelfPermission(ScanQRActivity.this, Manifest.permission.ACCESS_COARSE_LOCATION) != PackageManager.PERMISSION_GRANTED
                    || ContextCompat.checkSelfPermission(ScanQRActivity.this, Manifest.permission.ACCESS_FINE_LOCATION) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(ScanQRActivity.this, new String[]{Manifest.permission.ACCESS_COARSE_LOCATION, Manifest.permission.ACCESS_FINE_LOCATION},
                        PERMISSI_REQUESTCODE_LOCATION);
            } else if (ContextCompat.checkSelfPermission(ScanQRActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                ActivityCompat.requestPermissions(ScanQRActivity.this, new String[]{Manifest.permission.CAMERA}, PERMISSI_REQUESTCODE_CAMERA);
            } else {
                initCamera(holder);
            }
        }
    }

在权限申请回调中处理：若打开权限时，点击了”拒绝”，则不会弹出权限申请框。解决方法是在权限回调里面判断无权限要给出相关提示，引导用户去设置或跳转到设置打开权限。

@Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        switch (requestCode) {
            case PERMISSI_REQUESTCODE_CAMERA:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED) {
                    initCamera(holder);
                } else {
                    showToast("you denied camera permission!");
                }
                break;
            case PERMISSI_REQUESTCODE_LOCATION:
                if (grantResults.length > 0 && grantResults[0] == PackageManager.PERMISSION_GRANTED && grantResults[1] == PackageManager.PERMISSION_GRANTED) {
                    showToast("the location permission is ok!");
                } else {
                    showToast("you denied the location permission!");
                    Intent intent = new Intent(ScanQRActivity.this, NoPermissionActivity.class);
                    intent.putExtra("cameraOrNot", "gps");
                    startActivityForResult(intent, 102);
                }
                if (ContextCompat.checkSelfPermission(ScanQRActivity.this, Manifest.permission.CAMERA) != PackageManager.PERMISSION_GRANTED) {
                    ActivityCompat.requestPermissions(ScanQRActivity.this, new String[]{Manifest.permission.CAMERA}, PERMISSI_REQUESTCODE_CAMERA);
                } else {
                    initCamera(holder);
                }
                break;
        }
    }