二维码的生成与解析

本是古典何须时尚 2022-09-25 00:22 214阅读 0赞

## 二维码的生成与解析 ##

#### 二维码的原理简介：二维码 （2-dimensional bar code），是用某种特定的几何图形按一定规律在平面（二维方向上）分布的黑白相间的图形记录数据符号信息的。二维码中的黑白色表示二进制的0和1，所以信息可以通过一定的编码方式，将信息编入进二维码中。二维码具有多种编码，常用的有：PDF417、QR Code、Code 49、Code 16K、Code One等。 ####

![这里写图片描述][20160803183659994]

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#### 效果图 ####

![这里写图片描述][20160803185021507]

以下是二维码生成代码：

#### 界面布局 ####

<?xml version="1.0" encoding="utf-8"?>
    <LinearLayout 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:padding="16dp" android:orientation="vertical" tools:context="www.weshared.demo2.MainActivity">
    
        <EditText android:id="@+id/edit_url" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="输入信息" />
    
        <Button android:id="@+id/btn_get_erweima" android:layout_width="match_parent" android:text="生成二维码" android:layout_height="wrap_content" />
    
        <ImageView android:layout_marginTop="100dp" android:layout_gravity="center" android:id="@+id/iv_erweima" android:layout_width="200dp" android:layout_height="200dp" />
    </LinearLayout>

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MainActivity中代码

public class MainActivity extends AppCompatActivity implements View.OnClickListener, View.OnLongClickListener { 
    
        private EditText editText;
        private Button btn;
        private ImageView imageView;
        private boolean isShow;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) {
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_main);
            init();
            initListener();
        }
    
        private void init() {
            editText = (EditText) findViewById(R.id.edit_url);
            btn = (Button) findViewById(R.id.btn_get_erweima);
            imageView = (ImageView) findViewById(R.id.iv_erweima);
        }
    
        private void initListener() {
            btn.setOnClickListener(this);
            imageView.setOnLongClickListener(this);
        }
    
        @Override
        public void onClick(View view) {
            switch (view.getId()) {
                case R.id.btn_get_erweima:
                    getErWeiMa();
                    isShow = true;
                    break;
            }
    
        }
    
    
        @Override
        public boolean onLongClick(View view) {
            scanErWeiMa();
            return true;
        }
    
        private void scanErWeiMa() {
            if (isShow) {
                BitmapDrawable drawable = (BitmapDrawable) imageView.getDrawable();
                Bitmap bitmap = drawable.getBitmap();
                int w = bitmap.getWidth();
                int h = bitmap.getHeight();
                int[] row = new int[w * h];
                bitmap.getPixels(row, 0, w, 0, 0, w, h);//获取bitmap的像素点
    
                Hashtable<DecodeHintType, String> table = new Hashtable<>();
                table.put(DecodeHintType.CHARACTER_SET, "utf-8");//设置编码格式
    
                QRCodeReader reader = new QRCodeReader();
                BinaryBitmap binaryBitmap = new BinaryBitmap(new HybridBinarizer(new RGBLuminanceSource(w, h, row)));
                try {
                    Result result = reader.decode(binaryBitmap, table);
                    String content = result.getText();
                    Toast.makeText(getApplicationContext(), content, Toast.LENGTH_SHORT).show();
                } catch (NotFoundException e) {
                    e.printStackTrace();
                } catch (ChecksumException e) {
                    e.printStackTrace();
                } catch (FormatException e) {
                    e.printStackTrace();
                }
            }
        }
    
        public void getErWeiMa() {
            String content = editText.getText().toString().trim();
            if (TextUtils.isEmpty(content)) return;
            Bitmap bitmap = createErWeiMa(content);
            if (bitmap == null) return;
            imageView.setImageBitmap(bitmap);
        }
    
        private Bitmap createErWeiMa(String content) {
    
            QRCodeWriter writer = new QRCodeWriter();
            try {
                BitMatrix matrix = writer.encode(content,
                        BarcodeFormat.QR_CODE, //二维码的编码格式，与‘QRCodeWriter’对应
                        imageView.getMeasuredWidth(),
                        imageView.getMeasuredHeight());
    
                return matrixChangeBitmap(matrix);
    
            } catch (WriterException e) {
                e.printStackTrace();
            }
            return null;
        }
    
        private Bitmap matrixChangeBitmap(BitMatrix matrix) {
            if (matrix == null) throw new NullPointerException("matrix is null");
    
            int width = matrix.getWidth();
            int height = matrix.getHeight();
            int[] row = new int[width * height];
    
            for (int i = 0; i < width; i++) {
                for (int j = 0; j < height; j++) {
                    int color = Color.WHITE;
                    if (matrix.get(i, j)) {
                        color = Color.BLACK;
                    }
                    row[i + j * width] = color;
                }
            }
    
            Bitmap bitmap = Bitmap.createBitmap(width, height, Bitmap.Config.ARGB_8888);
            bitmap.setPixels(row, 0, width, 0, 0, width, height);
            return bitmap;
        }
    }

[20160803183659994]: /images/20220719/5e29e46fffda40af963039d4e574ae32.png
[20160803185021507]: /images/20220719/e80f5e684f0d4dd5b28a935288d16572.png