问如何在另一个活动中启动活动？Zxing

EN

                try {
                    Intent intent = new Intent("com.google.zxing.client.android.SCAN");
                    intent.putExtra("com.google.zxing.client.android.SCAN.SCAN_MODE", "QR_CODE_MODE");
                    intent.putExtra("com.google.zxing.client.android.SCAN.SCAN_MODE", "PRODUCT_MODE");
                    startActivityForResult(intent, 0);
                }
                catch (ActivityNotFoundException e) {


                }

public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == 0) {

            if (resultCode == RESULT_OK) {

                String contents = intent.getStringExtra("SCAN_RESULT");

                String format = intent.getStringExtra("SCAN_RESULT_FORMAT");


                Toast.makeText(this, contents, Toast.LENGTH_SHORT).show();

            } else if (resultCode == RESULT_CANCELED) {
                // Handle cancel
            }
        }
    }