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安卓如果調用usb設備？

发布时间：2022-03-26 14:51:03编辑：雪饮阅读（）

 最近有一個需求：

在一個安卓設備上面有内置一個打印設備，該安卓設備是加油站那邊好像自己定制的一個安卓7.1系統。
那個提供了一個android sdk（就是一個jar包）。
然後我們前端是基於uniapp開發的，那麽前端這邊直接使用這個jar包並調用usb設備去打印貌似就很困難了。
我的想法是用原生安卓調用這個sdk實現打印功能，然後咱們那個uniapp開發的apk就負責通過intent意圖參數來調用這個打印專用的安卓應用程序。這樣對於uniapp那邊就方便多了。
 
那麽這裏主要是原生實現調用usb設備去打印的功能。
那麽首先我是在app/build.gradle中加載了這個Android sdk上面提供的jar包：
plugins {
    id 'com.android.application'
}
 
android {
    compileSdk 32
 
    defaultConfig {
        applicationId "com.example.getusbdeviceforjava71"
        minSdk 25
        targetSdk 32
        versionCode 1
        versionName "1.0"
 
        testInstrumentationRunner "androidx.test.runner.AndroidJUnitRunner"
    }
 
    buildTypes {
        release {
            minifyEnabled false
            proguardFiles getDefaultProguardFile('proguard-android-optimize.txt'), 'proguard-rules.pro'
       }
    }
    compileOptions {
        sourceCompatibility JavaVersion.VERSION_1_8
        targetCompatibility JavaVersion.VERSION_1_8
    }
}
 
dependencies {
 
    implementation 'androidx.appcompat:appcompat:1.3.0'
    implementation 'com.google.android.material:material:1.4.0'
    implementation 'androidx.constraintlayout:constraintlayout:2.0.4'
    implementation files('D:\\androidProject\\getUsbDeviceForJava7.1\\printersdkv5.6.jar')
    testImplementation 'junit:junit:4.13.2'
    androidTestImplementation 'androidx.test.ext:junit:1.1.3'
    androidTestImplementation 'androidx.test.espresso:espresso-core:3.4.0'
}
然後接下來是主程序邏輯：
MainActivity.java：
package com.example.getusbdeviceforjava71;
 
import androidx.appcompat.app.AppCompatActivity;
 
import android.annotation.SuppressLint;
import android.content.Context;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbManager;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.util.Log;
 
import com.printer.sdk.PrinterConstants;
import com.printer.sdk.PrinterInstance;
 
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
 
public class MainActivity extends AppCompatActivity {
    PrinterInstance myPrinter;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
 
 
        /*获取usb设备*/
        HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
        Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
        List<UsbDevice> usbDevices = new ArrayList<>();
        while (deviceIterator.hasNext()) {
            UsbDevice device = deviceIterator.next();
            usbDevices.add(device);
            String ProductName=device.getProductName();
            if("SPRT Printer".equals(ProductName)){
                Log.i("usb设备", "可能是打印设备SPRT Printer");
                //获取打印机实体类
                myPrinter = PrinterInstance.getPrinterInstance(MainActivity.this, device, new Handler() {
                    @Override
                    public void handleMessage(Message msg) {
                        //msg.what
                        //Log.i("msg.what", Message.ty);
 
                        switch (msg.what) {
                            case PrinterConstants.Connect.SUCCESS:
                                Log.i("msg.what", "连接成功！");
                               // myPrinter.sendBytesData();
                                myPrinter.initPrinter();
                                //myPrinter.setPrinter();
                                if (myPrinter != null&&myPrinter.getCurrentStatus() == 0){
                                    myPrinter.setPrinter(PrinterConstants.Command.ALIGN, PrinterConstants.Command.ALIGN_CENTER);
                                    String content="";
                                    for(int i=0;i<10;i++){
                                        content+="printTest杜佳鹏!\r\n";
                                    }
                                    myPrinter.printText(content);
                                    Log.i("打印指令", "打印指令已发出");
                                    int printingStatus=myPrinter.getPrintingStatus(5000);
 
                                    Log.i("打印机状态",String.valueOf(printingStatus));
                                }
                                else{
                                    Log.i("打印机异常","打印机状态异常：通信异常，缺纸，开盖，纸将尽");
                                }
 
                                break;
                            case PrinterConstants.Connect.FAILED:
                                Log.i("msg.what", "连接失败！");
                                break;
                            case PrinterConstants.Connect.CLOSED:
                                Log.i("msg.what", "连接关闭！");
                                break;
                            case PrinterConstants.Connect.NODEVICE:
                                Log.i("msg.what", "NODEVICE！");
                                break;
                            default:
                                Log.i("msg.what", "其它未知情况");
                                break;
                        }
                    }
 
                });
                myPrinter.openConnection();
            }
            Log.i("获取的usb设备列表", "getDeviceList: " +ProductName);
        }
        //获取usb设备end
    }
 
}
這裏紅色重點標記的地方就是獲取usb設備的核心代碼，不過該代碼是運行在安卓7.1的，并且這個安卓設備不是主流安卓設備，應該是加油站那邊自定義的，所以也僅限參考價值。
最後就是打印的效果了：