The URL is converted into a QR code.

The URL is converted into a QR code.

Reprinted please indicate the source: http://www.cnblogs.com/cnwutianhao/p/6685804.html

 

QR code has become an inaccessible product in our daily life. There will be QR codes on train tickets, scenic spots, and supermarket payments.

This article converts a URL into a QR code.

First look at the sample image

From the example, we can clearly see that the URL is converted into a QR code.

Follow me to implement this function.

 

Import open-source libraries provided by Google

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

To explain the core part: QR Code Conversion

① Generate a QR code Bitmap

Public static boolean createQRImage (String content, int widthPix, int heightPix, Bitmap logoBm, String filePath) {try {if (content = null | "". equals (content) {return false;} // configure the Map parameter <EncodeHintType, Object> hints = new HashMap <> (); hints. put (EncodeHintType. CHARACTER_SET, "UTF-8"); // fault tolerance level hints. put (EncodeHintType. ERROR_CORRECTION, ErrorCorrectionLevel. h); // set the width of the blank margin hints. put (EncodeHintTy Pe. MARGIN, 2); // default is 4 // image data conversion, using the matrix conversion BitMatrix bitMatrix = new QRCodeWriter (). encode (content, BarcodeFormat. QR_CODE, widthPix, heightPix, hints); int [] pixels = new int [widthPix * heightPix]; // The following uses the QR code algorithm to generate images of QR codes one by one, // The two for loops are the results of the horizontal column scan of the image. for (int y = 0; y 
② Add a Logo in the middle of the QR code
Private static Bitmap addLogo (Bitmap src, Bitmap logo) {if (src = null) {return null;} if (logo = null) {return src ;} // obtain the image width and height 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 ;} // The logo size is 1/5 float 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 Create a directory for storing QR code files
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 Create a database tool class to store temporary data
Public class SPUtil {private static final String CONFIG = "config";/*** get the SharedPreferences Instance Object ** @ param fileName */private static SharedPreferences getSharedPreference (String fileName) {return QRCodeApplication. getInstance (). getSharedPreferences (fileName, Context. MODE_PRIVATE);}/*** save a value of the String type! */Public static void putString (String key, String value) {SharedPreferences. editor editor = getSharedPreference (CONFIG ). edit (); editor. putString (key, value ). apply ();}/*** get String value */public static String getString (String key, String defValue) {SharedPreferences sharedPreference = getSharedPreference (CONFIG); return sharedPreference. getString (key, defValue );}}
⑤ Display the QR code
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 ("pai_code_filepath", ""); imageView. setImageBitmap (BitmapFactory. decodeFile (preFilePath);} else {SPUtil. putString ("pai_code_content", text); final String filePath = getFileRoot (mContext) + File. separator + "qr _" + System. currentTimeMillis () + ". jpg "; SPUtil. putString ("share_code_filePath", filePath); // when the QR code image is large, it may take a long time to generate and save the image. Therefore, the new Thread (new Runnable () {@ Override public void run () {boolean success = QRCodeUtil. createQRImage (text, 800,800, BitmapFactory. decodeResource (mContext. getResources (), centerPhoto), filePath); if (success) {mContext. runOnUiThread (new Runnable () {@ Override public void run () {imageView. setImageBitmap (BitmapFactory. decodeFile (filePath ));}});}}}). start ();}}
 
Construct a class for the input page and use the Bundle to pass the value through <key, value> (the value will be changed to the MVVM-DataBinding form later)
Public class ContentActivity extends AppCompatActivity implements View. onClickListener {private EditText etUrl; private Button btnConvert; @ Override protected 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) ;}@ Override public 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); // when the input box is empty, the user is prompted if (str_url.equals ("https: //") {Toast. makeText (getApplicationContext (), "the input box cannot be blank", Toast. LENGTH_SHORT ). show ();} else {Intent intent = new Intent (ContentActivity. this, MainActivity. class); intent. putExtras (bundle); startActivity (intent) ;}break; default: break ;}}}
 
Display the QR code image on the page (the MVVM-DataBinding format will be changed later)
public class MainActivity extends AppCompatActivity {    private ImageView iv;//    private String url = "http://weibo.com/cnwutianhao";    @Override    protected 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);    }}
 
Layout File
① Enter the page (it will be changed to the DataBinding form later)
<? 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"> <EditText android: id = "@ + id/et_url" android: layout_width = "match_parent" android: layout_height = "50dp" android: layout_marginTop = "100dp" android: hint = "Enter the URL" android: inputType = "textUri"/> <Button android: id = "@ + id/btn_convert" android: layout_width = "wrap_content" android: layout_height = "wrap_content" android: Rule = "true" android: layout_centerHorizontal = "true" android: layout_marginBottom = "20dp" android: text = "convert to QR code"/> </RelativeLayout>
② QR code Display page
<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">    <ImageView        android:id="@+id/iv_qrcode"        android:layout_width="220dp"        android:layout_height="220dp"        android:layout_centerInParent="true"        android:layout_marginTop="40dp"        android:background="#FFFFFF" /></RelativeLayout>
 
The source code has been uploaded to Github. Welcome to Star and Fork. THX
Https://github.com/cnwutianhao/QRCode
 
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