Question

我是Android开发的新手。目前正在开发扫描二维码的基本Android应用程序。对于演示，我得到了源代码。但是当我试图运行应用程序时。它需要从Playstore下载Barcode Scanner应用程序。我需要做出改变的地方。谢谢

    public class AndroidBarcodeQrExample extends Activity {
    static final String ACTION_SCAN = "com.google.zxing.client.android.SCAN";

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        //set the main content layout of the Activity
        setContentView(R.layout.activity_main);
    }

    //product barcode mode
    public void scanBar(View v) {
        try {
            //start the scanning activity from the com.google.zxing.client.android.SCAN intent
            Intent intent = new Intent(ACTION_SCAN);
            intent.putExtra("SCAN_MODE", "PRODUCT_MODE");
            startActivityForResult(intent, 0);
        } catch (ActivityNotFoundException anfe) {
            //on catch, show the download dialog
            showDialog(AndroidBarcodeQrExample.this, "No Scanner Found", "Download a scanner code activity?", "Yes", "No").show();
        }
    }

    //product qr code mode
    public void scanQR(View v) {
        try {
            //start the scanning activity from the com.google.zxing.client.android.SCAN intent
            Intent intent = new Intent(ACTION_SCAN);
            intent.putExtra("SCAN_MODE", "QR_CODE_MODE");
            startActivityForResult(intent, 0);
        } catch (ActivityNotFoundException anfe) {
            //on catch, show the download dialog
            showDialog(AndroidBarcodeQrExample.this, "No Scanner Found", "Download a scanner code activity?", "Yes", "No").show();
        }
    }

    //alert dialog for downloadDialog
    private static AlertDialog showDialog(final Activity act, CharSequence title, CharSequence message, CharSequence buttonYes, CharSequence buttonNo) {
        AlertDialog.Builder downloadDialog = new AlertDialog.Builder(act);
        downloadDialog.setTitle(title);
        downloadDialog.setMessage(message);
        downloadDialog.setPositiveButton(buttonYes, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialogInterface, int i) {
                Uri uri = Uri.parse("market://search?q=pname:" + "com.google.zxing.client.android");
                Intent intent = new Intent(Intent.ACTION_VIEW, uri);
                try {
                    act.startActivity(intent);
                } catch (ActivityNotFoundException anfe) {

                }
            }
        });
        downloadDialog.setNegativeButton(buttonNo, new DialogInterface.OnClickListener() {
            public void onClick(DialogInterface dialogInterface, int i) {
            }
        });
        return downloadDialog.show();
    }

    //on ActivityResult method
    public void onActivityResult(int requestCode, int resultCode, Intent intent) {
        if (requestCode == 0) {
            if (resultCode == RESULT_OK) {
                //get the extras that are returned from the intent
                String contents = intent.getStringExtra("SCAN_RESULT");
                String format = intent.getStringExtra("SCAN_RESULT_FORMAT");
                Toast toast = Toast.makeText(this, "Content:" + contents + " Format:" + format, Toast.LENGTH_LONG);
                toast.show();
            }
        }
    }
}

Answer 1

为什么我需要安装条形码扫描仪才能运行此Android应用

您的代码正在从条形码扫描仪应用程序启动活动。因此，您需要安装条形码扫描仪应用程序才能使startActivityForResult()次呼叫正常工作。

我需要进行更改

您需要删除上面代码清单中的所有内容。然后，您需要找到符合您需求的a barcode-scanning library。

Answer 2

static final String ACTION_SCAN = "com.google.zxing.client.android.SCAN"; Intent intent = new Intent(ACTION_SCAN);

以上行意味着，您正在为该指定操作创建意图。这是谷歌的xzing应用程序包中的活动。因此需要特定的应用程序。这是android的力量。您只需指定ACTION_DIAL等即可轻松通过应用程序调用来电.Android将根据其处理的内容（由清单公开）调用正确的应用。

假设您有两个拨号器应用，您将可以选择选择哪个。

在您的情况下，由于您使用zxing，预计特定的应用程序将出现。请记住，您不是在编写整个条形码应用程序，只是调用它们的操作。

为什么我需要安装Barcode Scanner才能运行此Android应用程序

2 个答案: