如何使用相机在离线模式下执行条形码扫描，因为它可以扫描条形码并将数字返回给我？
答案 0 :(得分：0)
您可以使用提供独立条形码阅读器应用程序的Zxing项目来实现这一点，该应用程序（通过Android的意图机制）可以被其他希望集成条形码扫描的应用程序调用。
Zxing项目的代码是：
IntentIntegrator类：
/*
* Copyright 2009 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.integration.android;
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;
/**
* <p>A utility class which helps ease integration with Barcode Scanner via {@link Intent}s. This is a simple
* way to invoke barcode scanning and receive the result, without any need to integrate, modify, or learn the
* project's source code.</p>
*
* <h2>Initiating a barcode scan</h2>
*
* <p>To integrate, create an instance of {@code IntentIntegrator} and call {@link #initiateScan()} and wait
* for the result in your app.</p>
*
* <p>It does require that the Barcode Scanner (or work-alike) application is installed. The
* {@link #initiateScan()} method will prompt the user to download the application, if needed.</p>
*
* <p>There are a few steps to using this integration. First, your {@link Activity} must implement
* the method {@link Activity#onActivityResult(int, int, Intent)} and include a line of code like this:</p>
*
* <pre>{@code
* public void onActivityResult(int requestCode, int resultCode, Intent intent) {
* IntentResult scanResult = IntentIntegrator.parseActivityResult(requestCode, resultCode, intent);
* if (scanResult != null) {
* // handle scan result
* }
* // else continue with any other code you need in the method
* ...
* }
* }</pre>
*
* <p>This is where you will handle a scan result.</p>
*
* <p>Second, just call this in response to a user action somewhere to begin the scan process:</p>
*
* <pre>{@code
* IntentIntegrator integrator = new IntentIntegrator(yourActivity);
* integrator.initiateScan();
* }</pre>
*
* <p>Note that {@link #initiateScan()} returns an {@link AlertDialog} which is non-null if the
* user was prompted to download the application. This lets the calling app potentially manage the dialog.
* In particular, ideally, the app dismisses the dialog if it's still active in its {@link Activity#onPause()}
* method.</p>
*
* <p>You can use {@link #setTitle(String)} to customize the title of this download prompt dialog (or, use
* {@link #setTitleByID(int)} to set the title by string resource ID.) Likewise, the prompt message, and
* yes/no button labels can be changed.</p>
*
* <p>Finally, you can use {@link #addExtra(String, Object)} to add more parameters to the Intent used
* to invoke the scanner. This can be used to set additional options not directly exposed by this
* simplified API.</p>
*
* <p>By default, this will only allow applications that are known to respond to this intent correctly
* do so. The apps that are allowed to response can be set with {@link #setTargetApplications(List)}.
* For example, set to {@link #TARGET_BARCODE_SCANNER_ONLY} to only target the Barcode Scanner app itself.</p>
*
* <h2>Sharing text via barcode</h2>
*
* <p>To share text, encoded as a QR Code on-screen, similarly, see {@link #shareText(CharSequence)}.</p>
*
* <p>Some code, particularly download integration, was contributed from the Anobiit application.</p>
*
* <h2>Enabling experimental barcode formats</h2>
*
* <p>Some formats are not enabled by default even when scanning with {@link #ALL_CODE_TYPES}, such as
* PDF417. Use {@link #initiateScan(java.util.Collection)} with
* a collection containing the names of formats to scan for explicitly, like "PDF_417", to use such
* formats.</p>
*
* @author Sean Owen
* @author Fred Lin
* @author Isaac Potoczny-Jones
* @author Brad Drehmer
* @author gcstang
*/
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(
BS_PACKAGE, // Barcode Scanner
BSPLUS_PACKAGE, // Barcode Scanner+
BSPLUS_PACKAGE + ".simple" // Barcode Scanner+ Simple
// 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.<br>
* 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 (ResolveInfo availableApp : availableApps) {
String packageName = availableApp.activityInfo.packageName;
if (targetApplications.contains(packageName)) {
return packageName;
}
}
}
return null;
}
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类：
/*
* Copyright 2009 ZXing authors
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
package com.google.zxing.integration.android;
/**
* <p>Encapsulates the result of a barcode scan invoked through {@link IntentIntegrator}.</p>
*
* @author Sean Owen
*/
public final 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();
}
}
在所需的活动中呼叫Zxing：
//instantiate ZXing integration class
IntentIntegrator scanIntegrator = new IntentIntegrator(this);
//start scanning
scanIntegrator.initiateScan();
通过以下方式获取扫描结果：
if (scanningResult != null) {
//get content from Intent Result
String scanContent = scanningResult.getContents();
//get format name of data scanned
String scanFormat = scanningResult.getFormatName();
}
有关详情，请参阅此zxing
希望这有帮助！答案 1 :(得分：0)
看看Zxing图书馆：
https://github.com/zxing/zxing
还有一个嵌入式版本：
https://github.com/journeyapps/zxing-android-embedded
将扫描仪活动添加到您的清单：
<activity
android:name="com.google.zxing.client.android.CaptureActivity"
android:configChanges="orientation|keyboardHidden"
android:windowSoftInputMode="stateAlwaysHidden" >
<intent-filter>
<action android:name="com.google.zxing.client.android.SCAN" />
<category android:name="android.intent.category.DEFAULT" />
</intent-filter>
</activity>
并用
打开它 Intent intent = new Intent(Intents.Scan.ACTION);
intent.setPackage(this.getPackageName());
//Add any optional extras to pass
intent.putExtra(Intents.Scan.MODE, Intents.Scan.ONE_D_MODE);
//Launch
startActivityForResult(intent, SCAN_REQUEST_CODE);
并使用
获取结果@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
// Check which request we're responding to
if (requestCode == SCAN_REQUEST_CODE) {
// Make sure the request was successful
if (resultCode == RESULT_OK) {
String result = data.getStringExtra(Intents.Scan.RESULT);
...
}
}
}