【Android】——創建與識別二維碼

先什麼都不說，直接上圖



好了，想必大家也知道，在做Android開發的時候二維碼你其實可以直接在ImageView控件中放一張二維碼圖片，然後進行適配的，但是這樣就會有幾個個弊端，一，分辨率問題，需要對ImageView進行屏幕適配；二，對二維碼內容的識別上會花更多的時間，更多的代碼去實現怎麼解析二維碼上的數據，這無疑增加了開發過程中大量的時間和經歷，成本提高了不少。
下面是我的一次經歷寫的一個文檔，希望對需要的朋友些許幫助。
首先是一個xml佈局文件

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:background="#333333"
    tools:context="com.liushunlin.qrcodes.MainActivity">
    <Button
        android:onClick="generate"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="點擊生成二維碼"
        android:layout_alignParentTop="true"/>
    <ImageView
        android:id="@+id/iv"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="10dp"
        android:layout_centerInParent="true"/>
    <TextView
        android:layout_above="@+id/iv"
        android:id="@+id/content"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_centerInParent="true"
        android:textSize="20sp"
        android:text="這裏是二維碼信息"/>
    <Button
        android:onClick="go"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="識別圖中二維碼"
        android:layout_alignParentBottom="true"/>

</RelativeLayout>

這裏是Activity，裏面都有註釋，這裏就不多說了

package com.liushunlin.qrcodes;

import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Canvas;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import com.google.zxing.BarcodeFormat;
import com.google.zxing.BinaryBitmap;
import com.google.zxing.ChecksumException;
import com.google.zxing.DecodeHintType;
import com.google.zxing.EncodeHintType;
import com.google.zxing.FormatException;
import com.google.zxing.MultiFormatReader;
import com.google.zxing.NotFoundException;
import com.google.zxing.PlanarYUVLuminanceSource;
import com.google.zxing.Result;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.common.HybridBinarizer;
import com.google.zxing.qrcode.QRCodeReader;
import com.google.zxing.qrcode.QRCodeWriter;
import com.google.zxing.qrcode.decoder.ErrorCorrectionLevel;

import java.util.HashMap;
import java.util.Hashtable;

public class MainActivity extends AppCompatActivity {
    private ImageView iv;
    private TextView content;
    private Bitmap bitmap;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        iv = (ImageView) findViewById(R.id.iv);
        content = (TextView) findViewById(R.id.content);
        iv.setOnLongClickListener(new View.OnLongClickListener() {
            @Override
            public boolean onLongClick(View view) {
                identityQRCode();
                return false;
            }
        });
    }

    /**
     * 生成二維碼
     * @param content   生成二維碼的文本內容
     * @param width     二維碼圖片的寬
     * @param height    二維碼圖片的高
     * @return          bitmap對象
     */
    private Bitmap generateBitmap(String content,int width, int height) {
        QRCodeWriter qrCodeWriter = new QRCodeWriter();
        HashMap hints = new HashMap<>();
        hints.put(EncodeHintType.CHARACTER_SET, "utf-8");
        //容錯率等級
        hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.M);
        //邊距默認爲5,這裏設置爲1
        hints.put(EncodeHintType.MARGIN,1);
        try {
            BitMatrix encode = qrCodeWriter.encode(content, BarcodeFormat.QR_CODE, width, height, hints);
            int[] pixels = new int[width * height];
            for (int i = 0; i < height; i++) {
                for (int j = 0; j < width; j++) {
                    if (encode.get(j, i)) {
                        pixels[i * width + j] = 0x00000000;
                    } else {
                        pixels[i * width + j] = 0xffffffff;
                    }
                }
            }
            return Bitmap.createBitmap(pixels, 0, width, width, height, Bitmap.Config.RGB_565);
        } catch (WriterException e) {
            e.printStackTrace();
        }
        return null;
    }


    public void generate(View view) {
	    //第一個參數：需要生成的二維碼攜帶的內容
	    //第二個參數：需要生成的二維碼的width
	    //第三個參數：需要生成的二維碼的height
        Bitmap qrBitmap = generateBitmap("http://www.csdn.net",400, 400);
        bitmap = qrBitmap;
        Bitmap logoBitmap = BitmapFactory.decodeResource(getResources(), R.mipmap.ic_launcher);
        Bitmap bitmap = addLogo(qrBitmap, logoBitmap);
        iv.setImageBitmap(bitmap);
    }

    /**
     * 給二維碼添加中心LOGO
     * @param qrBitmap
     * @param logoBitmap
     * @return
     */
    private Bitmap addLogo(Bitmap qrBitmap, Bitmap logoBitmap) {
        int qrBitmapWidth = qrBitmap.getWidth();
        int qrBitmapHeight = qrBitmap.getHeight();
        int logoBitmapWidth = logoBitmap.getWidth();
        int logoBitmapHeight = logoBitmap.getHeight();
        Bitmap blankBitmap = Bitmap.createBitmap(qrBitmapWidth, qrBitmapHeight, Bitmap.Config.ARGB_8888);
        Canvas canvas = new Canvas(blankBitmap);
        canvas.drawBitmap(qrBitmap, 0, 0, null);
        canvas.save(Canvas.ALL_SAVE_FLAG);
        float scaleSize = 1.0f;
        while ((logoBitmapWidth / scaleSize) > (qrBitmapWidth / 5) || (logoBitmapHeight / scaleSize) > (qrBitmapHeight / 5)) {
            scaleSize *= 2;
        }
        float sx = 1.0f / scaleSize;
        canvas.scale(sx, sx, qrBitmapWidth / 2, qrBitmapHeight / 2);
        canvas.drawBitmap(logoBitmap, (qrBitmapWidth - logoBitmapWidth) / 2, (qrBitmapHeight - logoBitmapHeight) / 2, null);
        canvas.restore();
        return blankBitmap;
    }

    public void go(View view) {
        identityQRCode();
    }

    public void identityQRCode(){
        Hashtable<DecodeHintType, Object> hints = new Hashtable<DecodeHintType, Object>();
        hints.put(DecodeHintType.CHARACTER_SET, "utf-8");
        RGBLuminanceSource source = new RGBLuminanceSource(bitmap);
        BinaryBitmap bitmap1 = new BinaryBitmap(new HybridBinarizer(source));
        QRCodeReader reader2 = new QRCodeReader();
        Result result = null;
        try {
            result = reader2.decode(bitmap1, hints);
        } catch (NotFoundException e) {
            e.printStackTrace();
        } catch (ChecksumException e) {
            e.printStackTrace();
        } catch (FormatException e) {
            e.printStackTrace();
        }
        content.setText(result.getText());
    }
}

還有一個工具類，具體就不贅述了，慢慢理解會看的懂的

package com.liushunlin.qrcodes;

import com.google.zxing.LuminanceSource;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import java.io.FileNotFoundException;

public final class RGBLuminanceSource extends LuminanceSource {

    private final byte[] luminances;

    public RGBLuminanceSource(String path) throws FileNotFoundException {
        this(loadBitmap(path));
    }

    public RGBLuminanceSource(Bitmap bitmap) {
        super(bitmap.getWidth(), bitmap.getHeight());

        int width = bitmap.getWidth();
        int height = bitmap.getHeight();
        int[] pixels = new int[width * height];
        bitmap.getPixels(pixels, 0, width, 0, 0, width, height);

        
        luminances = new byte[width * height];
        for (int y = 0; y < height; y++) {
            int offset = y * width;
            for (int x = 0; x < width; x++) {
                int pixel = pixels[offset + x];
                int r = (pixel >> 16) & 0xff;
                int g = (pixel >> 8) & 0xff;
                int b = pixel & 0xff;
                if (r == g && g == b) {
                    luminances[offset + x] = (byte) r;
                } else {
                    luminances[offset + x] = (byte) ((r + g + g + b) >> 2);
                }
            }
        }
    }

    @Override
    public byte[] getRow(int y, byte[] row) {
        if (y < 0 || y >= getHeight()) {
            throw new IllegalArgumentException(
                    "Requested row is outside the image: " + y);
        }
        int width = getWidth();
        if (row == null || row.length < width) {
            row = new byte[width];
        }

        System.arraycopy(luminances, y * width, row, 0, width);
        return row;
    }

  
    @Override
    public byte[] getMatrix() {
        return luminances;
    }

    private static Bitmap loadBitmap(String path) throws FileNotFoundException {
        Bitmap bitmap = BitmapFactory.decodeFile(path);
        if (bitmap == null) {
            throw new FileNotFoundException("Couldn't open " + path);
        }
        return bitmap;
    }

}

完了…
等等…………
還有個Jar包沒放，下面是鏈接，請自行下載

鏈接：https://pan.baidu.com/s/1i4YOW89 密碼：pt8c
長按以及點擊都有實現，各位老司機自己琢磨吧。