当扫描结果与表格的项目编号字段匹配时，我正在按钮单击时进行条形码扫描，以将数量计数字段增加一个表格。如果扫描结果与项目编号匹配，则应更新该行的计数数量。我无法获得扫描结果本身。获得NullPointerException。
这是我的代码。
这是来自zxing的两个Java文件。
IntentIntegrator.java
package com.example.mis;
import java.util.Arrays;
import java.util.Collection;
import java.util.Collections;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import android.app.Activity;
import android.app.AlertDialog;
import android.content.ActivityNotFoundException;
import android.content.DialogInterface;
import android.content.Intent;
import android.content.pm.PackageManager;
import android.content.pm.ResolveInfo;
import android.net.Uri;
import android.os.Bundle;
import android.util.Log;
public class IntentIntegrator {
public static final int REQUEST_CODE = 0x0000c0de; // Only use bottom 16
// bits
private static final String TAG = IntentIntegrator.class.getSimpleName();
public static final String DEFAULT_TITLE = "Install Barcode Scanner?";
public static final String DEFAULT_MESSAGE = "This application requires Barcode Scanner. Would you like to install it?";
public static final String DEFAULT_YES = "Yes";
public static final String DEFAULT_NO = "No";
private static final String BS_PACKAGE = "com.google.zxing.client.android";
private static final String BSPLUS_PACKAGE = "com.srowen.bs.android";
// supported barcode formats
public static final Collection<String> PRODUCT_CODE_TYPES = list("UPC_A",
"UPC_E", "EAN_8", "EAN_13", "RSS_14");
public static final Collection<String> ONE_D_CODE_TYPES = list("UPC_A",
"UPC_E", "EAN_8", "EAN_13", "CODE_39", "CODE_93", "CODE_128",
"ITF", "RSS_14", "RSS_EXPANDED");
public static final Collection<String> QR_CODE_TYPES = Collections
.singleton("QR_CODE");
public static final Collection<String> DATA_MATRIX_TYPES = Collections
.singleton("DATA_MATRIX");
public static final Collection<String> ALL_CODE_TYPES = null;
public static final List<String> TARGET_BARCODE_SCANNER_ONLY = Collections
.singletonList(BS_PACKAGE);
public static final List<String> TARGET_ALL_KNOWN = list(BSPLUS_PACKAGE, // Barcode
// Scanner+
BSPLUS_PACKAGE + ".simple", // Barcode Scanner+ Simple
BS_PACKAGE // Barcode Scanner
// What else supports this intent?
);
private final Activity activity;
private String title;
private String message;
private String buttonYes;
private String buttonNo;
private List<String> targetApplications;
private final Map<String, Object> moreExtras;
public IntentIntegrator(Activity activity) {
this.activity = activity;
title = DEFAULT_TITLE;
message = DEFAULT_MESSAGE;
buttonYes = DEFAULT_YES;
buttonNo = DEFAULT_NO;
targetApplications = TARGET_ALL_KNOWN;
moreExtras = new HashMap<String, Object>(3);
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public void setTitleByID(int titleID) {
title = activity.getString(titleID);
}
public String getMessage() {
return message;
}
public void setMessage(String message) {
this.message = message;
}
public void setMessageByID(int messageID) {
message = activity.getString(messageID);
}
public String getButtonYes() {
return buttonYes;
}
public void setButtonYes(String buttonYes) {
this.buttonYes = buttonYes;
}
public void setButtonYesByID(int buttonYesID) {
buttonYes = activity.getString(buttonYesID);
}
public String getButtonNo() {
return buttonNo;
}
public void setButtonNo(String buttonNo) {
this.buttonNo = buttonNo;
}
public void setButtonNoByID(int buttonNoID) {
buttonNo = activity.getString(buttonNoID);
}
public Collection<String> getTargetApplications() {
return targetApplications;
}
public final void setTargetApplications(List<String> targetApplications) {
if (targetApplications.isEmpty()) {
throw new IllegalArgumentException("No target applications");
}
this.targetApplications = targetApplications;
}
public void setSingleTargetApplication(String targetApplication) {
this.targetApplications = Collections.singletonList(targetApplication);
}
public Map<String, ?> getMoreExtras() {
return moreExtras;
}
public final void addExtra(String key, Object value) {
moreExtras.put(key, value);
}
/**
* Initiates a scan for all known barcode types.
*/
public final AlertDialog initiateScan() {
return initiateScan(ALL_CODE_TYPES);
}
/**
* Initiates a scan only for a certain set of barcode types, given as
* strings corresponding to their names in ZXing's {@code BarcodeFormat}
* class like "UPC_A". You can supply constants like
* {@link #PRODUCT_CODE_TYPES} for example.
*
* @return the {@link AlertDialog} that was shown to the user prompting them
* to download the app if a prompt was needed, or null otherwise
*/
public final AlertDialog initiateScan(
Collection<String> desiredBarcodeFormats) {
Intent intentScan = new Intent(BS_PACKAGE + ".SCAN");
intentScan.addCategory(Intent.CATEGORY_DEFAULT);
// check which types of codes to scan for
if (desiredBarcodeFormats != null) {
// set the desired barcode types
StringBuilder joinedByComma = new StringBuilder();
for (String format : desiredBarcodeFormats) {
if (joinedByComma.length() > 0) {
joinedByComma.append(',');
}
joinedByComma.append(format);
}
intentScan.putExtra("SCAN_FORMATS", joinedByComma.toString());
}
String targetAppPackage = findTargetAppPackage(intentScan);
if (targetAppPackage == null) {
return showDownloadDialog();
}
intentScan.setPackage(targetAppPackage);
intentScan.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intentScan.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
attachMoreExtras(intentScan);
startActivityForResult(intentScan, REQUEST_CODE);
return null;
}
/**
* Start an activity. This method is defined to allow different methods of
* activity starting for newer versions of Android and for compatibility
* library.
*
* @param intent
* Intent to start.
* @param code
* Request code for the activity
* @see android.app.Activity#startActivityForResult(Intent, int)
* @see android.app.Fragment#startActivityForResult(Intent, int)
*/
protected void startActivityForResult(Intent intent, int code) {
activity.startActivityForResult(intent, code);
}
private String findTargetAppPackage(Intent intent) {
PackageManager pm = activity.getPackageManager();
List<ResolveInfo> availableApps = pm.queryIntentActivities(intent,
PackageManager.MATCH_DEFAULT_ONLY);
if (availableApps != null) {
for (String targetApp : targetApplications) {
if (contains(availableApps, targetApp)) {
return targetApp;
}
}
}
return null;
}
private static boolean contains(Iterable<ResolveInfo> availableApps,
String targetApp) {
for (ResolveInfo availableApp : availableApps) {
String packageName = availableApp.activityInfo.packageName;
if (targetApp.equals(packageName)) {
return true;
}
}
return false;
}
private AlertDialog showDownloadDialog() {
AlertDialog.Builder downloadDialog = new AlertDialog.Builder(activity);
downloadDialog.setTitle(title);
downloadDialog.setMessage(message);
downloadDialog.setPositiveButton(buttonYes,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
String packageName = targetApplications.get(0);
Uri uri = Uri.parse("market://details?id="
+ packageName);
Intent intent = new Intent(Intent.ACTION_VIEW, uri);
try {
activity.startActivity(intent);
} catch (ActivityNotFoundException anfe) {
// Hmm, market is not installed
Log.w(TAG,
"Google Play is not installed; cannot install "
+ packageName);
}
}
});
downloadDialog.setNegativeButton(buttonNo,
new DialogInterface.OnClickListener() {
@Override
public void onClick(DialogInterface dialogInterface, int i) {
}
});
return downloadDialog.show();
}
/**
* <p>
* Call this from your {@link Activity}'s
* {@link Activity#onActivityResult(int, int, Intent)} method.
* </p>
*
* @return null if the event handled here was not related to this class, or
* else an {@link IntentResult} containing the result of the scan.
* If the user cancelled scanning, the fields will be null.
*/
public static IntentResult parseActivityResult(int requestCode,
int resultCode, Intent intent) {
if (requestCode == REQUEST_CODE) {
if (resultCode == Activity.RESULT_OK) {
String contents = intent.getStringExtra("SCAN_RESULT");
String formatName = intent.getStringExtra("SCAN_RESULT_FORMAT");
byte[] rawBytes = intent.getByteArrayExtra("SCAN_RESULT_BYTES");
int intentOrientation = intent.getIntExtra(
"SCAN_RESULT_ORIENTATION", Integer.MIN_VALUE);
Integer orientation = intentOrientation == Integer.MIN_VALUE ? null
: intentOrientation;
String errorCorrectionLevel = intent
.getStringExtra("SCAN_RESULT_ERROR_CORRECTION_LEVEL");
return new IntentResult(contents, formatName, rawBytes,
orientation, errorCorrectionLevel);
}
return new IntentResult();
}
return null;
}
/**
* Defaults to type "TEXT_TYPE".
*
* @see #shareText(CharSequence, CharSequence)
*/
public final AlertDialog shareText(CharSequence text) {
return shareText(text, "TEXT_TYPE");
}
/**
* Shares the given text by encoding it as a barcode, such that another user
* can scan the text off the screen of the device.
*
* @param text
* the text string to encode as a barcode
* @param type
* type of data to encode. See
* {@code com.google.zxing.client.android.Contents.Type}
* constants.
* @return the {@link AlertDialog} that was shown to the user prompting them
* to download the app if a prompt was needed, or null otherwise
*/
public final AlertDialog shareText(CharSequence text, CharSequence type) {
Intent intent = new Intent();
intent.addCategory(Intent.CATEGORY_DEFAULT);
intent.setAction(BS_PACKAGE + ".ENCODE");
intent.putExtra("ENCODE_TYPE", type);
intent.putExtra("ENCODE_DATA", text);
String targetAppPackage = findTargetAppPackage(intent);
if (targetAppPackage == null) {
return showDownloadDialog();
}
intent.setPackage(targetAppPackage);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
intent.addFlags(Intent.FLAG_ACTIVITY_CLEAR_WHEN_TASK_RESET);
attachMoreExtras(intent);
activity.startActivity(intent);
return null;
}
private static List<String> list(String... values) {
return Collections.unmodifiableList(Arrays.asList(values));
}
private void attachMoreExtras(Intent intent) {
for (Map.Entry<String, Object> entry : moreExtras.entrySet()) {
String key = entry.getKey();
Object value = entry.getValue();
// Kind of hacky
if (value instanceof Integer) {
intent.putExtra(key, (Integer) value);
} else if (value instanceof Long) {
intent.putExtra(key, (Long) value);
} else if (value instanceof Boolean) {
intent.putExtra(key, (Boolean) value);
} else if (value instanceof Double) {
intent.putExtra(key, (Double) value);
} else if (value instanceof Float) {
intent.putExtra(key, (Float) value);
} else if (value instanceof Bundle) {
intent.putExtra(key, (Bundle) value);
} else {
intent.putExtra(key, value.toString());
}
}
}
}
IntentResult.java
package com.example.mis;
public class IntentResult {
private final String contents;
private final String formatName;
private final byte[] rawBytes;
private final Integer orientation;
private final String errorCorrectionLevel;
IntentResult() {
this(null, null, null, null, null);
}
IntentResult(String contents,
String formatName,
byte[] rawBytes,
Integer orientation,
String errorCorrectionLevel) {
this.contents = contents;
this.formatName = formatName;
this.rawBytes = rawBytes;
this.orientation = orientation;
this.errorCorrectionLevel = errorCorrectionLevel;
}
/**
* @return raw content of barcode
*/
public String getContents() {
return contents;
}
/**
* @return name of format, like "QR_CODE", "UPC_A". See {@code BarcodeFormat} for more format names.
*/
public String getFormatName() {
return formatName;
}
/**
* @return raw bytes of the barcode content, if applicable, or null otherwise
*/
public byte[] getRawBytes() {
return rawBytes;
}
/**
* @return rotation of the image, in degrees, which resulted in a successful scan. May be null.
*/
public Integer getOrientation() {
return orientation;
}
/**
* @return name of the error correction level used in the barcode, if applicable
*/
public String getErrorCorrectionLevel() {
return errorCorrectionLevel;
}
@Override
public String toString() {
StringBuilder dialogText = new StringBuilder(100);
dialogText.append("Format: ").append(formatName).append('\n');
dialogText.append("Contents: ").append(contents).append('\n');
int rawBytesLength = rawBytes == null ? 0 : rawBytes.length;
dialogText.append("Raw bytes: (").append(rawBytesLength).append(" bytes)\n");
dialogText.append("Orientation: ").append(orientation).append('\n');
dialogText.append("EC level: ").append(errorCorrectionLevel).append('\n');
return dialogText.toString();
}
}
这是我正在实施条形码扫描的活动
public class InventoryCount extends Activity {
private Button mbtn_scan;
mbtn_scan.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View arg0) {
// TODO Auto-generated method stub
IntentIntegrator integrator = new IntentIntegrator(
InventoryCount.this);
integrator.initiateScan();
}
});
}
public void onActivityResult(int requestCode, int resultCode, Intent intent) {
// retrieve result of scanning - instantiate ZXing object
IntentResult scanningResult = IntentIntegrator.parseActivityResult(
requestCode, resultCode, intent);
// check we have a valid result
try {
if (resultCode == RESULT_OK) {
Log.i("Scanning Result ", "" + scanningResult);
Toast.makeText(
InventoryCount.this,
"Scanning success the content is : "
+ scanningResult.getContents(),
Toast.LENGTH_SHORT).show();
String sr = scanningResult.getContents();
getBarCodeData(sr);
} else if (resultCode == RESULT_CANCELED) {
Toast toast = Toast.makeText(InventoryCount.this,
"Scanning Cancelled!", Toast.LENGTH_SHORT);
toast.show();
}
} catch (Exception e) {
System.out.println("Error on scanning: "+e);
}
}
public void getBarCodeData(String itmNumber) {
Cursor c;
try {
String qtyCountQry = "SELECT " + DatabaseHandler.KEY_QTYCOUNTED
+ " FROM " + DatabaseHandler.TABLE_MIC2 + " WHERE "
+ DatabaseHandler.KEY_ITEMNUMBER + "='" + itmNumber + "'";
SQLiteDatabase sq = db.getReadableDatabase();
c = sq.rawQuery(qtyCountQry, null);
c.moveToFirst();
String q2 = c.getString(c
.getColumnIndex(DatabaseHandler.KEY_QTYCOUNTED));
Toast.makeText(InventoryCount.this, "Quantity Count is " + q2,
Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(InventoryCount.this, "Exception " + e,
Toast.LENGTH_SHORT).show();
}
}
我刚尝试显示扫描结果，如果匹配itemnumber，它将显示该行中的相应数量，如上面的代码所示。但截至目前，甚至没有显示扫描结果。帮助我..还说如何将数量增加一个并在db中更新它。
答案 0 :(得分：1)
尝试通过扩展CaptureActivity类来使用zxing库。
public class ScannerData extends CaptureActivity {
Handler handler = null;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.activity_scanner);
}
@Override
public void handleDecode(final Result rawResult, Bitmap barcode,
float scaleFactor) {
// TODO Auto-generated method stub
handler = getHandler();
handler.sendEmptyMessageDelayed(R.id.restart_preview,
CaptureActivity.BULK_MODE_SCAN_DELAY_MS);
String mQrcode = rawResult.getText().toString();
}
}
使用这样的代码。
你可以在这里获得qr码
String mQrcode = rawResult.getText（）。toString（）;
在Xml中，您需要包含capture.xml
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/container"
android:layout_width="match_parent"
android:layout_height="match_parent">
<RelativeLayout
android:id="@+id/frameLayout1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerVertical="true"
android:layout_gravity="center_horizontal"
android:layout_marginRight="25dp">
<FrameLayout
android:layout_width="510dp"
android:layout_height="310dp"
android:background="@drawable/scanner_box"
android:layout_gravity="center" >
<include
android:layout_width="750dp"
android:layout_height="450dp"
android:layout_gravity="center"
android:layout_marginBottom="50dp"
android:layout_marginRight="110dp"
layout="@layout/capture" />
</FrameLayout>
</RelativeLayout>
</RelativeLayout>