Andoid开发中生成二维码
第一步：
确定我们二维码的位置，即是在我们应用的哪个页面的哪个位置，简单讲就是用一个ImageView把二维码展示出来，我们就把二维码展示在下面布局activity_main.xml中的ImageView上：
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <LinearLayout android:layout_width="fill_parent" android:layout_height="fill_parent" android:orientation="horizontal" android:gravity="center_horizontal" > <ImageView android:id="@+id/imag" android:layout_width="100dp" android:layout_height="100dp" android:scaleType="fitXY" android:src="@drawable/ic_launcher" android:layout_gravity="center" ></ImageView> </LinearLayout> </LinearLayout>
第二步：定义一个生成二维码的工具类：QRUtils.java (注意：定义之前不要忘记在项目中要导入ZXing相关的jar包)
既core.jar这个包 jar包下载地址
package com.utils;
import java.util.EnumMap;
import java.util.Map;
import android.graphics.Bitmap;
import android.graphics.Canvas;
import android.graphics.Matrix;
import android.graphics.Paint;
import android.text.TextUtils;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.MultiFormatWriter;
import com.google.zxing.common.BitMatrix;
public class QRUtils {
private static final int WHITE = 0xFFFFFFFF;
private static final int BLACK = 0xFF000000;
/**
* 将字符串按照指定大小生成二维码图片
*/
public static Bitmap encodeToQR(String contentsToEncode, int dimension)
throws Exception {
if (TextUtils.isEmpty(contentsToEncode))
return null;
BarcodeFormat format = BarcodeFormat.QR_CODE;
Map hints = new EnumMap(EncodeHintType.class);
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
BitMatrix result = new MultiFormatWriter().encode(contentsToEncode,
format, dimension, dimension, hints);
int width = result.getWidth();
int height = result.getHeight();
int[] pixels = new int[width * height];
for (int y = 0; y < height; y++) {
int offset = y * width;
for (int x = 0; x < width; x++) {
pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
}
}
Bitmap bitmap = Bitmap.createBitmap(width, height,
Bitmap.Config.ARGB_8888);
bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
return bitmap;
}
public static Bitmap encodeToQRWidth(String contentsToEncode, int dimension)
throws Exception {
if (TextUtils.isEmpty(contentsToEncode))
return null;
BarcodeFormat format = BarcodeFormat.QR_CODE;
@SuppressWarnings("unchecked")
Map hints = new EnumMap(EncodeHintType.class);
hints.put(EncodeHintType.CHARACTER_SET, "UTF-8");
BitMatrix result = new MultiFormatWriter().encode(contentsToEncode,
format, dimension, dimension, hints);
int width = result.getWidth();
int height = result.getHeight();
boolean isFirstBlack = true;
int startX = 0;
int startY = 0;
int[] pixels = new int[width * height];
for (int y = 0; y < height; y++) {
int offset = y * width;
for (int x = 0; x < width; x++) {
pixels[offset + x] = result.get(x, y) ? BLACK : WHITE;
if (result.get(x, y) && isFirstBlack) {
isFirstBlack = false;
startX = x;
startY = y;
}
}
}
Bitmap bitmap = Bitmap.createBitmap(width, height,
Bitmap.Config.ARGB_8888);
bitmap.setPixels(pixels, 0, width, 0, 0, width, height);
Matrix m = new Matrix();
float sx = (width + 2f * startX) / width;
float sy = (height + 2f * startY) / height;
m.postScale(sx, sy);
Bitmap qrBitmap = Bitmap.createBitmap(width, height,
Bitmap.Config.ARGB_8888);
Canvas canvas = new Canvas(qrBitmap);
canvas.translate(-startX, -startY);
Paint paint = new Paint();
paint.setAntiAlias(true);
canvas.drawBitmap(bitmap, m, paint);
canvas.save();
return qrBitmap;
}
}
第三步：在我们既我们的主Activity：MainActivity.java
package com.action;
import android.app.Activity;
import android.graphics.Bitmap;
import android.os.Bundle;
import android.util.DisplayMetrics;
import android.view.ViewGroup;
import android.widget.ImageView;
import android.widget.Toast;
import com.utils.*;
public class MainActivity extends Activity {
private ImageView imag;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initViews();
}
protected void initViews() {
imag = (ImageView) findViewById(R.id.imag);
DisplayMetrics outMetrics = new DisplayMetrics();
getWindowManager().getDefaultDisplay().getMetrics(outMetrics);
int w = outMetrics.widthPixels * 8 / 11;// 设置宽度
ViewGroup.LayoutParams layoutParams = imag.getLayoutParams();
layoutParams.height = layoutParams.width = w;// 设置高度
imag.setLayoutParams(layoutParams);
try {
Bitmap bitmap = QRUtils.encodeToQRWidth(
"http://write.blog.csdn.net/", w);// 要生成二维码的内容，我这就是一个网址
imag.setImageBitmap(bitmap);
} catch (Exception e) {
e.printStackTrace();
Toast.makeText(this, "生成二维码失败", Toast.LENGTH_SHORT);
}
}
}
三步完成我们的二维码生成，是不是很简单！！