URL转换成二维码

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二维码已经成为我们日常生活中的一个不可获取的产物，火车票上，景区门票，超市付款等等都会有二维码的身影。

本文将实现由URL转换成二维码的过程。

先看一下示例图

从示例图中我们可以清晰地看到，URL被转换成了二维码。

下面跟随我来一起实现这个功能。

导入Google提供的开源库

compile 'com.google.zxing:core:3.3.0'

来讲解一下核心的部分：二维码转换

①生成二维码Bitmap

public static boolean createQRImage(String content, int widthPix, int heightPix, Bitmap logoBm, String filePath) {try {if (content == null || "".equals(content)) {return false;}//配置参数Map<EncodeHintType, Object> hints = new HashMap<>();hints.put(EncodeHintType.CHARACTER_SET, "utf-8");//容错级别
            hints.put(EncodeHintType.ERROR_CORRECTION, ErrorCorrectionLevel.H);//设置空白边距的宽度hints.put(EncodeHintType.MARGIN, 2); //default is 4// 图像数据转换，使用了矩阵转换BitMatrix bitMatrix = new QRCodeWriter().encode(content, BarcodeFormat.QR_CODE, widthPix, heightPix, hints);int[] pixels = new int[widthPix * heightPix];// 下面这里按照二维码的算法，逐个生成二维码的图片，// 两个for循环是图片横列扫描的结果for (int y = 0; y < heightPix; y++) {for (int x = 0; x < widthPix; x++) {if (bitMatrix.get(x, y)) {pixels[y * widthPix + x] = 0xff000000;} else {pixels[y * widthPix + x] = 0xffffffff;}}}// 生成二维码图片的格式，使用ARGB_8888Bitmap bitmap = Bitmap.createBitmap(widthPix, heightPix, Bitmap.Config.ARGB_8888);bitmap.setPixels(pixels, 0, widthPix, 0, 0, widthPix, heightPix);if (logoBm != null) {bitmap = addLogo(bitmap, logoBm);}//必须使用compress方法将bitmap保存到文件中再进行读取。直接返回的bitmap是没有任何压缩的，内存消耗巨大！return bitmap != null && bitmap.compress(Bitmap.CompressFormat.JPEG, 100, new FileOutputStream(filePath));} catch (WriterException | IOException e) {e.printStackTrace();}return false;}

②在二维码中间添加Logo图案

private static Bitmap addLogo(Bitmap src, Bitmap logo) {if (src == null) {return null;}if (logo == null) {return src;}//获取图片的宽高int srcWidth = src.getWidth();int srcHeight = src.getHeight();int logoWidth = logo.getWidth();int logoHeight = logo.getHeight();if (srcWidth == 0 || srcHeight == 0) {return null;}if (logoWidth == 0 || logoHeight == 0) {return src;}//logo大小为二维码整体大小的1/5float scaleFactor = srcWidth * 1.0f / 5 / logoWidth;Bitmap bitmap = Bitmap.createBitmap(srcWidth, srcHeight, Bitmap.Config.ARGB_8888);try {Canvas canvas = new Canvas(bitmap);canvas.drawBitmap(src, 0, 0, null);canvas.scale(scaleFactor, scaleFactor, srcWidth / 2, srcHeight / 2);canvas.drawBitmap(logo, (srcWidth - logoWidth) / 2, (srcHeight - logoHeight) / 2, null);canvas.save(Canvas.ALL_SAVE_FLAG);canvas.restore();} catch (Exception e) {bitmap = null;e.getStackTrace();}return bitmap;}

③创建二维码文件存储目录

private static String getFileRoot(Context context) {if (Environment.getExternalStorageState().equals(Environment.MEDIA_MOUNTED)) {File external = context.getExternalFilesDir(null);if (external != null) {return external.getAbsolutePath();}}return context.getFilesDir().getAbsolutePath();}

④创建数据库工具类来存储临时数据

public class SPUtil {private static final String CONFIG = "config";/*** 获取SharedPreferences实例对象** @param fileName*/private static SharedPreferences getSharedPreference(String fileName) {return QRCodeApplication.getInstance().getSharedPreferences(fileName, Context.MODE_PRIVATE);}/*** 保存一个String类型的值！*/public static void putString(String key, String value) {SharedPreferences.Editor editor = getSharedPreference(CONFIG).edit();editor.putString(key, value).apply();}/*** 获取String的value*/public static String getString(String key, String defValue) {SharedPreferences sharedPreference = getSharedPreference(CONFIG);return sharedPreference.getString(key, defValue);}}

⑤展示二维码

public static void showThreadImage(final Activity mContext, final String text, final ImageView imageView, final int centerPhoto) {String preContent = SPUtil.getString("share_code_content", "");if (text.equals(preContent)) {String preFilePath = SPUtil.getString("share_code_filePath", "");imageView.setImageBitmap(BitmapFactory.decodeFile(preFilePath));} else {SPUtil.putString("share_code_content", text);final String filePath = getFileRoot(mContext) + File.separator + "qr_" + System.currentTimeMillis() + ".jpg";SPUtil.putString("share_code_filePath", filePath);//二维码图片较大时，生成图片、保存文件的时间可能较长，因此放在新线程中new Thread(new Runnable() {@Overridepublic void run() {boolean success = QRCodeUtil.createQRImage(text, 800, 800, BitmapFactory.decodeResource(mContext.getResources(), centerPhoto),filePath);if (success) {mContext.runOnUiThread(new Runnable() {@Overridepublic void run() {imageView.setImageBitmap(BitmapFactory.decodeFile(filePath));}});}}}).start();}}

构造一个输入页面的类，使用Bundle通过<key,value>传值（后期会改为MVVM-DataBinding形式）

public class ContentActivity extends AppCompatActivity implements View.OnClickListener {private EditText etUrl;private Button btnConvert;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_content);initView();}private void initView() {etUrl = (EditText) findViewById(R.id.et_url);btnConvert = (Button) findViewById(R.id.btn_convert);btnConvert.setOnClickListener(this);}@Overridepublic void onClick(View v) {switch (v.getId()) {case R.id.btn_convert:String str_url = "https://" + etUrl.getText().toString();Bundle bundle = new Bundle();bundle.putString("url", str_url);// 当输入框为空时，提示用户if (str_url.equals("https://")) {Toast.makeText(getApplicationContext(), "输入框不能为空", Toast.LENGTH_SHORT).show();} else {Intent intent = new Intent(ContentActivity.this, MainActivity.class);intent.putExtras(bundle);startActivity(intent);}break;default:break;}}
}

将二维码图片展示在页面上（后期会改为MVVM-DataBinding形式）

public class MainActivity extends AppCompatActivity {private ImageView iv;//    private String url = "http://weibo.com/cnwutianhao";
@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);String str_url = getIntent().getExtras().getString("url");iv = (ImageView) findViewById(R.id.iv_qrcode);QRCodeUtil.showThreadImage(this, str_url, iv, R.mipmap.ic_launcher);}
}

布局文件

①输入页面（后期会改为DataBinding形式）

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"android:padding="10dp"><EditTextandroid:id="@+id/et_url"android:layout_width="match_parent"android:layout_height="50dp"android:layout_marginTop="100dp"android:hint="请输入网址"android:inputType="textUri" /><Buttonandroid:id="@+id/btn_convert"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentBottom="true"android:layout_centerHorizontal="true"android:layout_marginBottom="20dp"android:text="转换成二维码" /></RelativeLayout>

②二维码展示页面

<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"tools:context="com.tnnowu.android.qrcode.MainActivity"><ImageViewandroid:id="@+id/iv_qrcode"android:layout_width="220dp"android:layout_height="220dp"android:layout_centerInParent="true"android:layout_marginTop="40dp"android:background="#FFFFFF" /></RelativeLayout>