1.控件

1.1按钮

获取按钮：

Button btn_scan_view=(Button) findViewById(R.id.button_get);

按钮点击事件：

 //点击开始生成按钮监听事件
        btn_get.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
               //点击事件内容
            }
        });

1.2 输入框

输入框：

EditText edittext=findViewById(R.id.editTextText);//输入框

获取输入内容：

String input= edittext.getText().toString();

1.3 图像

获取图像控件：

  ImageView img_view=(ImageView)findViewById(R.id.imageView);

将图像填充到控件：

img_view.setImageBitmap();

2.页面跳转

2.1 跳转到自定义页面

使用Intent来实现页面跳转
首先，我们需要创建一个新的Android Activity。在Android Studio中，可以通过以下步骤实现：
在项目的结构视图中，右键点击app -> New -> Activity -> Blank Activity，然后给新的Activity命名并选择放在哪个文件夹下。
在AndroidManifest.xml文件中，我们需要为新的Activity注册一个类别。

//监听按钮，如果点击，就跳转
ntent intent = new Intent();
 //前一个（MainActivity.this）是目前页面，后面一个是要跳转的下一个页面
 intent.setClass(MainActivity.this,ScanActivity.class);//ScanActivity修改为待跳转页面
startActivity(intent);

3.代码示例（生成、扫描二维码）

3.1 创建项目及准备工作

创建项目修改镜像提速(settings.gradle.kts)文件修改为：

pluginManagement {
    repositories {
        maven { setUrl("https://maven.aliyun.com/repository/public") }
        maven { setUrl("https://maven.aliyun.com/repository/central") }
        google()
        mavenCentral()
        gradlePluginPortal()
    }
}
dependencyResolutionManagement {
    repositoriesMode.set(RepositoriesMode.FAIL_ON_PROJECT_REPOS)
    repositories {
        maven { setUrl("https://maven.aliyun.com/repository/public") }
        maven { setUrl("https://maven.aliyun.com/repository/central") }
        google()
        mavenCentral()
    }
}

maven添加jar包,在build.gradle.kts添加：

implementation("com.journeyapps:zxing-android-embedded:3.6.0")

gradle下载版本:

https://services.gradle.org/distributions/

3.2 主页面（生成二维码）：

代码：

package com.example.week08_or;
import androidx.appcompat.app.AppCompatActivity;
import android.annotation.SuppressLint;
import android.content.Intent;
import android.graphics.Bitmap;
import android.graphics.Color;
import android.os.Bundle;
import android.text.TextUtils;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ImageView;

import com.google.zxing.BarcodeFormat;
import com.google.zxing.EncodeHintType;
import com.google.zxing.WriterException;
import com.google.zxing.common.BitMatrix;
import com.google.zxing.qrcode.QRCodeWriter;

import java.util.Hashtable;

public class MainActivity extends AppCompatActivity {
    Button btn_get;
    Button btn_scan_view;
    ImageView img_view;
    EditText edittext;

    @SuppressLint("MissingInflatedId")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn_get=(Button) findViewById(R.id.button_get);
        img_view=(ImageView)findViewById(R.id.imageView);
        btn_scan_view=(Button)findViewById(R.id.button_page);//跳转页面
        edittext =findViewById(R.id.editTextText);//输入框

        //点击开始生成按钮监听事件
        btn_get.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                String input= edittext.getText().toString();
                //调用CreateUtil类生成二维码后显示在界面上
                img_view.setImageBitmap(createQRCode(input,img_view.getWidth(),img_view.getHeight()));
            }
        });
        btn_scan_view.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //监听按钮，如果点击，就跳转
                Intent intent = new Intent();
                //前一个（MainActivity.this）是目前页面，后面一个是要跳转的下一个页面
                intent.setClass(MainActivity.this,ScanActivity.class);
                startActivity(intent);
            }
        });
    }

    //将输入的字符串转为图像
    public  Bitmap createQRCode(String codestring, int width, int height){
        try {
            //首先判断参数的合法性，要求字符串内容不能为空或图片长宽必须大于0
            if (TextUtils.isEmpty(codestring)||width<=0||height<=0){
                return null;
            }
            //设置二维码的相关参数，生成BitMatrix（位矩阵）对象
            Hashtable<EncodeHintType,String> hashtable=new Hashtable<>();
            hashtable.put(EncodeHintType.CHARACTER_SET,"utf-8");  //设置字符转码格式
            hashtable.put(EncodeHintType.ERROR_CORRECTION,"H");   //设置容错级别
            hashtable.put(EncodeHintType.MARGIN,"2"); //设置空白边距
            //encode需要抛出和处理异常
            BitMatrix bitMatrix=new QRCodeWriter().encode(codestring, BarcodeFormat.QR_CODE,width,height,hashtable);
            //再创建像素数组，并根据位矩阵为数组元素赋颜色值
            int[] pixel=new int[width*width];
            for (int h=0;h<height;h++){
                for (int w=0;w<width;w++){
                    if (bitMatrix.get(w,h)){
                        pixel[h*width+w]= Color.BLACK;  //设置黑色色块
                    }else{
                        pixel[h*width+w]=Color.WHITE;  //设置白色色块
                    }
                }
            }
            //创建bitmap对象
            //根据像素数组设置Bitmap每个像素点的颜色值，之后返回Bitmap对象
            Bitmap qrcodemap=Bitmap.createBitmap(width,height,Bitmap.Config.ARGB_8888);
            qrcodemap.setPixels(pixel,0,width,0,0,width,height);
            return qrcodemap;
        }catch (WriterException e){
            return null;
        }
    }
}

layout文件：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="301dp"
        android:layout_height="283dp"
        android:layout_marginStart="50dp"
        android:layout_marginEnd="50dp"
        android:layout_marginBottom="149dp"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/button_get"
        app:layout_constraintVertical_bias="1.0"
        app:srcCompat="@drawable/ic_launcher_background" />

    <Button
        android:id="@+id/button_get"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginEnd="21dp"
        android:layout_marginBottom="529dp"
        android:text="生成"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toEndOf="@+id/button_page"
        app:layout_constraintTop_toBottomOf="@+id/editTextText" />

    <EditText
        android:id="@+id/editTextText"
        android:layout_width="355dp"
        android:layout_height="78dp"
        android:ems="10"
        android:inputType="text"
        android:text="输入需生成的字符串"
        app:layout_constraintBottom_toTopOf="@+id/button_page"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <Button
        android:id="@+id/button_page"
        android:layout_width="108dp"
        android:layout_height="59dp"
        android:layout_marginStart="23dp"
        android:text="扫码页面"
        app:layout_constraintBaseline_toBaselineOf="@+id/button_get"
        app:layout_constraintEnd_toStartOf="@+id/button_get"
        app:layout_constraintStart_toStartOf="parent" />
</androidx.constraintlayout.widget.ConstraintLayout>

3.3 扫描二维码

代码：

package com.example.week08_or;

import android.annotation.SuppressLint;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.widget.Toast;

import androidx.appcompat.app.AppCompatActivity;

import com.google.zxing.integration.android.IntentIntegrator;
import com.google.zxing.integration.android.IntentResult;
import com.journeyapps.barcodescanner.CaptureActivity;

public class ScanActivity extends AppCompatActivity {
    Button btn_scan;
    Button btn_back;
    TextView textView;
    @SuppressLint("MissingInflatedId")
    @Override
    protected void onCreate(Bundle savedInstanceState){
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_scan);//绑定页面

        btn_scan=(Button)findViewById(R.id.btn_scan);
        btn_back=(Button) findViewById(R.id.button2);
        textView=(TextView)findViewById(R.id.textView);

        //扫描二维码按钮点击事件
        btn_scan.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                //.QR_CODE_TYPES 二维码
                //ONE_D_CODE_TYPES条形码
                //ALL_CODE_TYPES 所有类型
                new IntentIntegrator(ScanActivity.this).setDesiredBarcodeFormats(IntentIntegrator.ALL_CODE_TYPES)// 扫码的类型,可选：一维码，二维码，一/二维码
                        .setPrompt("请对准二维码")// 设置提示语
                        .setCameraId(0)// 选择摄像头,可使用前置或者后置
                        .setBeepEnabled(false)// 是否开启声音,扫完码之后会"哔"的一声
                        //.setBarcodeImageEnabled(true)// 扫完码之后生成二维码的图片
                        .setCaptureActivity(CaptureActivity.class)
                        .initiateScan();// 初始化扫码
            }
        });
        //返回上一页面
        btn_back.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                finish();
            }
        });
    }
    #回调函数，处理扫描结果
    @Override
    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
        IntentResult result = IntentIntegrator.parseActivityResult(requestCode, resultCode, data);
        if(result != null) {
            if(result.getContents() == null) {
                Toast.makeText(this, "Cancelled", Toast.LENGTH_LONG).show();
            } else {
                Toast.makeText(this, "Scanned: " + result.getContents(), Toast.LENGTH_LONG).show();
                textView.setText(result.getContents());
            }
        } else {
            super.onActivityResult(requestCode, resultCode, data);
        }
    }
}

布局文件：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <Button
        android:id="@+id/btn_scan"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="104dp"
        android:layout_marginBottom="90dp"
        android:text="扫描"
        app:layout_constraintBottom_toTopOf="@+id/textView"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/textView"
        android:layout_width="0dp"
        android:layout_height="0dp"
        android:layout_marginStart="55dp"
        android:layout_marginEnd="55dp"
        android:layout_marginBottom="275dp"
        android:text="扫描结果"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/btn_scan" />

    <Button
        android:id="@+id/button2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginStart="33dp"
        android:layout_marginTop="5dp"
        android:text="返回"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="@+id/btn_scan" />
</androidx.constraintlayout.widget.ConstraintLayout>

3.2.3 自定义扫描窗口

需要将

setCaptureActivity(CaptureActivity.class)

修改为：

setCaptureActivity(CustomCaptureActivity.class)
//CustomCaptureActivity为自定义activity名称。

Activity:

package com.example.week08_or;

import android.annotation.SuppressLint;
import android.os.Bundle;
import android.view.KeyEvent;

import androidx.annotation.NonNull;
import androidx.appcompat.app.AppCompatActivity;

import com.journeyapps.barcodescanner.CaptureManager;
import com.journeyapps.barcodescanner.DecoratedBarcodeView;

public class CustomCaptureActivity extends AppCompatActivity {
    private CaptureManager capture;
    private DecoratedBarcodeView barcodeScannerView;

    @SuppressLint("MissingInflatedId")
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);

        setContentView(R.layout.activity_custom_capture);// 自定义布局

        barcodeScannerView = (DecoratedBarcodeView) findViewById(R.id.dbv_custom);

        capture = new CaptureManager(this, barcodeScannerView);
        capture.initializeFromIntent(getIntent(), savedInstanceState);
        capture.decode();
    }

    @Override
    protected void onResume() {
        super.onResume();
        capture.onResume();
    }

    @Override
    protected void onPause() {
        super.onPause();
        capture.onPause();
    }

    @Override
    protected void onDestroy() {
        super.onDestroy();
        capture.onDestroy();
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        super.onSaveInstanceState(outState);
        capture.onSaveInstanceState(outState);
    }

    @Override
    public void onRequestPermissionsResult(int requestCode, @NonNull String permissions[], @NonNull int[] grantResults) {
        super.onRequestPermissionsResult(requestCode, permissions, grantResults);
        capture.onRequestPermissionsResult(requestCode, permissions, grantResults);
    }

    @Override
    public boolean onKeyDown(int keyCode, KeyEvent event) {
        return barcodeScannerView.onKeyDown(keyCode, event) || super.onKeyDown(keyCode, event);
    }
}

layout:

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent">

    <com.journeyapps.barcodescanner.DecoratedBarcodeView
        android:id="@+id/dbv_custom"
        android:layout_width="372dp"
        android:layout_height="683dp"
        android:layout_marginStart="20dp"
        android:layout_marginEnd="20dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.0"
        app:layout_constraintStart_toStartOf="parent"
        app:zxing_preview_scaling_strategy="fitXY"
        tools:layout_editor_absoluteY="19dp"
        tools:ignore="MissingConstraints" />

</androidx.constraintlayout.widget.ConstraintLayout>

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