android - Android 权限授予不断失败，按摩“包安装程序已停止”

Question

我想使用ZXingScannerView, 通过我的应用读取 QR 码。我需要授予相机使用权限ZXingScannerView，对吗？由于某种我不知道的原因，该视图不起作用。

无论如何，我是这么想的，所以我尝试授予权限，但它一直失败，说“包安装程序已停止”。我认为该错误是在线发生的 if(permissioncheck == PackageManager.PERMISSION_GRANTED)

这是完整的代码

ZXingScannerView mScanview;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    int permissioncheck = ContextCompat.checkSelfPermission(this, Manifest.permission.CAMERA);
    if(permissioncheck == PackageManager.PERMISSION_GRANTED){
        Toast.makeText(this, "ok", Toast.LENGTH_SHORT).show();
    }


    else {
        Toast.makeText(this, "not ok", Toast.LENGTH_SHORT).show();
        if(ActivityCompat.shouldShowRequestPermissionRationale(this, Manifest.permission.CAMERA)) {
            Toast.makeText(this, "ok?", Toast.LENGTH_SHORT).show();
        }
        else {
            ActivityCompat.requestPermissions(this, new String[] {Manifest.permission.CAMERA}, 1);
        }
    }




    Button button = (Button)findViewById(R.id.qr_button);
    button.setOnClickListener(new View.OnClickListener(){
        @Override
        public void onClick(View view){

            Toast.makeText(getApplicationContext(), "OK", Toast.LENGTH_SHORT).show();


            mScanview = new ZXingScannerView(getApplicationContext());
            setContentView(mScanview);

        }
    });

}

@Override
public void onRequestPermissionsResult(int reqCode, String permissions[], int[] grantResult){
    switch (reqCode){
        case 1: {
            if(grantResult.length > 0 && grantResult[0] == PackageManager.PERMISSION_GRANTED) {
                Toast.makeText(this, "ok", Toast.LENGTH_SHORT).show();
            }
            else {
                Toast.makeText(this, "not ok", Toast.LENGTH_SHORT).show();
            }

            return;
        }
    }
}

@Override
public void handleResult(Result result){
    Log.v("TAG", result.getText());
    Log.v("TAG", result.getBarcodeFormat().toString());
    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setTitle("Scan Result");
    builder.setMessage(result.getText());
    AlertDialog dialog = builder.create();
    dialog.show();
}

@Override
public void onPause() {
    super.onPause();
    mScanview.stopCamera();
}

或者，如果您知道在应用程序中实现 QR 码阅读器的更好方法，您能告诉我吗？