有谁知道 ZXing 条码扫描器库是否可以在 Xoom 上运行？我在 ZXing Google Group 上找到了一个帖子：http ://groups.google.com/group/zxing/browse_thread/thread/e16e74697d721e20
但仍然没有答案。任何帮助将不胜感激！
问问题
1001 次
2 回答
3
是的，它确实有效。代码是用java编写的，所以它几乎可以在任何设备上使用。永远，如果你尝试这个例子，它会使用旧的 android 2.x，它不能与蜂窝一起工作。因此，您将必须创建自己的相机包装器。有效的是图书馆，ZXing-1.7.zip。
这是使其工作所需的代码。请注意，它将在标题中显示条形码的内容。因此，使其工作所需的步骤：
- 在eclipse中新建一个名为“CameraPreview”的android项目，并将包名设置为“com.example.android.apis.graphics”。
- 从http://code.google.com/p/zxing/获取 ZXing-1.7.zip
- 从目录“ZXing-1.7.zip\zxing\core\src”中提取名为“com”的文件夹。
- 将提取的文件夹拖放到 Eclipse 中的 src 文件夹中：“CameraPreview\src”。它会询问您是否要替换“com”文件夹，说“是”。
- 获取“ZXing-1.7.zip\zxing\android\src\com\google\zxing\client\android\PlanarYUVLuminanceSource.java”的副本并将其放入名为“com.google.zxing.client.android”的新包中"（你必须创建一个新包）。
- 用这个替换代码“CameraPreviewActivity.java”：
CameraPreviewActivity.java:
/* Copyright (C) 2007 The Android Open Source Project */
package com.example.android.apis.graphics;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.ReaderException;
import com.google.zxing.Result;
import com.google.zxing.client.android.PlanarYUVLuminanceSource;
import com.google.zxing.common.HybridBinarizer;
import android.app.Activity;
import android.hardware.Camera;
import android.os.Bundle;
// ----------------------------------------------------------------------
public class CameraPreviewActivity extends Activity {
Preview mPreview;
Camera mCamera;
MultiFormatReader multiFormatReader;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
// Create a RelativeLayout container that will hold a SurfaceView,
// and set it as the content of our activity.
mPreview = new Preview(this);
setContentView(mPreview);
// Setup ZXing.
multiFormatReader = new MultiFormatReader();
CameraPreviewActivity.this.getActionBar().setTitle("");
}
@Override
protected void onResume() {
super.onResume();
mCamera = Camera.open();
mCamera.setPreviewCallback(new Camera.PreviewCallback() {
public void onPreviewFrame(byte[] data, Camera camera) {
Camera.Size size = camera.getParameters().getPreviewSize();
PlanarYUVLuminanceSource source = new PlanarYUVLuminanceSource(data, size.width, size.height, 0, 0,
size.width, size.height, false);
BinaryBitmap bitmap = new BinaryBitmap(new HybridBinarizer(source));
try {
Result r = multiFormatReader.decode(bitmap);
CameraPreviewActivity.this.getActionBar().setTitle(r.getText());
} catch (ReaderException re) {
// continue
}
}
});
mPreview.setCamera(mCamera);
}
@Override
protected void onPause() {
super.onPause();
// Because the Camera object is a shared resource, it's very
// important to release it when the activity is paused.
if (mCamera != null) {
mPreview.setCamera(null);
mCamera.setPreviewCallback(null);
mCamera.release();
mCamera = null;
}
}
}
创建一个名为Preview.java 的新类：
/* Copyright (C) 2007 The Android Open Source Project */
package com.example.android.apis.graphics;
import android.content.Context;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.view.ViewGroup;
import java.io.IOException;
import java.util.List;
// ----------------------------------------------------------------------
/**
* A simple wrapper around a Camera and a SurfaceView that renders a centered preview of the Camera
* to the surface. We need to center the SurfaceView because not all devices have cameras that
* support preview sizes at the same aspect ratio as the device's display.
*/
class Preview extends ViewGroup implements SurfaceHolder.Callback {
private final String TAG = "Preview";
SurfaceView mSurfaceView;
SurfaceHolder mHolder;
Size mPreviewSize;
List<Size> mSupportedPreviewSizes;
Camera mCamera;
Preview(Context context) {
super(context);
mSurfaceView = new SurfaceView(context);
addView(mSurfaceView);
// Install a SurfaceHolder.Callback so we get notified when the
// underlying surface is created and destroyed.
mHolder = mSurfaceView.getHolder();
mHolder.addCallback(this);
mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
}
public void setCamera(Camera camera) {
mCamera = camera;
if (mCamera != null) {
mSupportedPreviewSizes = mCamera.getParameters().getSupportedPreviewSizes();
requestLayout();
}
}
public void switchCamera(Camera camera) {
setCamera(camera);
try {
camera.setPreviewDisplay(mHolder);
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
Camera.Parameters parameters = camera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
camera.setParameters(parameters);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
// We purposely disregard child measurements because act as a
// wrapper to a SurfaceView that centers the camera preview instead
// of stretching it.
final int width = resolveSize(getSuggestedMinimumWidth(), widthMeasureSpec);
final int height = resolveSize(getSuggestedMinimumHeight(), heightMeasureSpec);
setMeasuredDimension(width, height);
if (mSupportedPreviewSizes != null) {
mPreviewSize = getOptimalPreviewSize(mSupportedPreviewSizes, width, height);
}
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
if (changed && getChildCount() > 0) {
final View child = getChildAt(0);
final int width = r - l;
final int height = b - t;
int previewWidth = width;
int previewHeight = height;
if (mPreviewSize != null) {
previewWidth = mPreviewSize.width;
previewHeight = mPreviewSize.height;
}
// Center the child SurfaceView within the parent.
if (width * previewHeight > height * previewWidth) {
final int scaledChildWidth = previewWidth * height / previewHeight;
child.layout((width - scaledChildWidth) / 2, 0,
(width + scaledChildWidth) / 2, height);
} else {
final int scaledChildHeight = previewHeight * width / previewWidth;
child.layout(0, (height - scaledChildHeight) / 2,
width, (height + scaledChildHeight) / 2);
}
}
}
public void surfaceCreated(SurfaceHolder holder) {
// The Surface has been created, acquire the camera and tell it where
// to draw.
try {
if (mCamera != null) {
mCamera.setPreviewDisplay(holder);
}
} catch (IOException exception) {
Log.e(TAG, "IOException caused by setPreviewDisplay()", exception);
}
}
public void surfaceDestroyed(SurfaceHolder holder) {
// Surface will be destroyed when we return, so stop the preview.
if (mCamera != null) {
mCamera.stopPreview();
}
}
private Size getOptimalPreviewSize(List<Size> sizes, int w, int h) {
final double ASPECT_TOLERANCE = 0.1;
double targetRatio = (double) w / h;
if (sizes == null) return null;
Size optimalSize = null;
double minDiff = Double.MAX_VALUE;
int targetHeight = h;
// Try to find an size match aspect ratio and size
for (Size size : sizes) {
double ratio = (double) size.width / size.height;
if (Math.abs(ratio - targetRatio) > ASPECT_TOLERANCE) continue;
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
// Cannot find the one match the aspect ratio, ignore the requirement
if (optimalSize == null) {
minDiff = Double.MAX_VALUE;
for (Size size : sizes) {
if (Math.abs(size.height - targetHeight) < minDiff) {
optimalSize = size;
minDiff = Math.abs(size.height - targetHeight);
}
}
}
return optimalSize;
}
public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
// Now that the size is known, set up the camera parameters and begin
// the preview.
Camera.Parameters parameters = mCamera.getParameters();
parameters.setPreviewSize(mPreviewSize.width, mPreviewSize.height);
requestLayout();
mCamera.setParameters(parameters);
mCamera.startPreview();
}
}
此外，替换AndroidManifest.xml的内容（这仅适用于 Android Honeycomb 3.2，如果您想使其在其他版本中工作，您必须更改此文件）：
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.android.apis.graphics"
android:versionCode="1"
android:versionName="1.0">
<uses-sdk android:minSdkVersion="13" />
<uses-permission android:name="android.permission.CAMERA" />
<uses-feature android:name="android.hardware.camera" />
<uses-feature android:name="android.hardware.camera.autofocus" />
<application android:icon="@drawable/icon" android:label="@string/app_name">
<activity android:name=".CameraPreviewActivity"
android:label="@string/app_name">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
抱歉版权标头，但两个类的大部分代码：CameraPreview.java和Preview.java来自http://developer.android.com/resources/samples/ApiDemos/src/com/example/android/apis/graphics /CameraPreview.html其中包含版权。该死的你。
于 2011-07-27T19:18:39.020 回答
0
核心库独立于任何特定设备或平台，所以“是”。Barcode Scanner 应用程序 3.6 版已确认可在 Xoom 上运行。
于 2011-06-03T17:33:57.970 回答