用于Android的USB主机

Question

我试图与我的freeduino板通信,这类似于arduino uno通过usb通过android设备'nexus 7',其中有4.2(果冻豆).

我使用开发人员指南在几个月内与设备进行通信但没有结果.我想我错过了一些东西.我想简单地显示我的freeduino板的供应商ID.我的清单文件看起来像这样.

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.usb_host_final_try"
    android:versionCode="1"
    android:versionName="1.0" >

    <uses-sdk
        android:minSdkVersion="8"
        android:targetSdkVersion="17" />

    <application
        android:allowBackup="true"
        android:icon="@drawable/ic_launcher"
        android:label="@string/app_name"
        android:theme="@style/AppTheme" >
        <activity
            android:name="com.example.usb_host_final_try.MainActivity"
            android:label="@string/app_name" >
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
            <intent-filter>
        <action android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED" />
    </intent-filter>

    <meta-data android:name="android.hardware.usb.action.USB_DEVICE_ATTACHED"
        android:resource="@xml/device_filter" />
        </activity>
    </application>

</manifest>

我在res/xml目录中创建了一个文件device_filter.看起来像这样

 <?xml version="1.0" encoding="utf-8"?>
<resources>
    <usb-device vendor-id="0403" product-id="07d7" />
</resources>

我的MainActivity.java有以下代码.

package com.example.usb_host_final_try;

import java.util.HashMap;

import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbManager;
import android.os.Build;
import android.os.Bundle;
import android.annotation.TargetApi;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {

    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Intent intent = new Intent();
        UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
        HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
        UsbDevice device = deviceList.get("deviceName");
        int vid=device.getVendorId();
        TextView tv = (TextView) findViewById(R.id.textview);
        tv.setText(Integer.toString(vid));
    }

请帮帮我,过去几个月我搞砸了.我试过这样做但它也没有用.

链接

链接

堆栈overfolow问题

堆栈溢出问题

我已经尝试了所有这些但仍未能成功.我还尝试使用if else循环来查看枚举是否有效,如果没有设备是settext到供应商ID,我将文本设置为未找到的设备.在模拟器上显示没有找到设备但是在我的平板电脑上我连接设备它强行关闭,否则它仍然显示没有设备发现没有任何连接.

堆栈跟踪在这里..

01-05 09:10:3​​5.364:W/Trace(1658):来自nativeGetEnabledTags的意外值:0 01-05 09:10:3​​5.364:W/Trace(1658):来自nativeGetEnabledTags的意外值:0 01-05 09:10 :35.464:W/Trace(1658):来自nativeGetEnabledTags的意外值:0 01-05 09:10:3​​5.464:W/Trace(1658):来自nativeGetEnabledTags的意外值:0 01-05 09:10:3​​5.624:D/AndroidRuntime (1658):关闭VM 01-05 09:10:3​​5.624:W/dalvikvm(1658):threadid = 1:线程退出未捕获异常(组= 0x40a70930)01-05 09:10:3​​5.644:E/AndroidRuntime( 1658):FATAL EXCEPTION:main 01-05 09:10:3​​5.644:E/AndroidRuntime(1658):java.lang.RuntimeException:无法启动活动ComponentInfo {com.example.usb_host_final_try/com.example.usb_host_final_try.MainActivity}: java.lang.NullPointerException 01-05 09:10:3​​5.644:E/AndroidRuntime(1658):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180)01-05 09:10:3​​5.644:E/AndroidRuntime(1658 ):在android.app.ActivityThread.handleLaunchActivity(Activ ityThread.java:2230)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):在android.app.ActivityThread.access $ 600(ActivityThread.java:141)01-05 09:10:3​​5.644:E/AndroidRuntime (1658):在android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1234)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):在android.os.Handler.dispatchMessage(Handler.java: 99)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):在android.os.Looper.loop(Looper.java:137)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):at android.app.ActivityThread.main(ActivityThread.java:5039)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):at java.lang.reflect.Method.invokeNative(Native Method)01-05 09:10 :35.644:E/AndroidRuntime(1658):at java.lang.reflect.Method.invoke(Method.java:511)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):at com.android.internal. os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:793)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)01 -05 09:10:3​​5.644:E/AndroidRu ntime(1658):at dalvik.system.NativeStart.main(Native Method)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):引起:java.lang.NullPointerException 01-05 09:10:3​​5.644: E/AndroidRuntime(1658):at com.example.usb_host_final_try.MainActivity.onCreate(MainActivity.java:35)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):at android.app.Activity.performCreate(Activity .java:5104)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):在android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)01-05 09:10:3​​5.644:E/AndroidRuntime(1658 ):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)01-05 09:10:3​​5.644:E/AndroidRuntime(1658):... 11更多01-05 09:10:46.0​​74:W/Trace (1712):来自nativeGetEnabledTags的意外值:0 01-05 09:10:46.0​​74:W/Trace(1712):来自nativeGetEnabledTags的意外值:0 01-05 09:10:46.754:D/AndroidRuntime(1712):关闭VM 01-05 09:10:46.754:W/dalvikvm(1712):threadid = 1:线程退出未捕获的异常(组= 0x40a709 30)01-05 09:10:46.766:E/AndroidRuntime(1712):FATAL EXCEPTION:main 01-05 09:10:46.766:E/AndroidRuntime(1712):java.lang.RuntimeException:无法启动活动ComponentInfo { com.example.usb_host_final_try/com.example.usb_host_final_try.MainActivity}:java.lang.NullPointerException 01-05 09:10:46.766:E/AndroidRuntime(1712):at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2180 )01-05 09:10:46.766:E/AndroidRuntime(1712):在android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2230)01-05 09:10:46.766:E/AndroidRuntime(1712):at android .app.ActivityThread.access $ 600(ActivityThread.java:141)01-05 09:10:46.766:E/AndroidRuntime(1712):at android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1234)01-05 09:10:46.766:E/AndroidRuntime(1712):在android.os.Handler.dispatchMessage(Handler.java:99)01-05 09:10:46.766:E/AndroidRuntime(1712):在android.os.Looper .loop(Looper.java:137)01-05 09:10:46.766:E/AndroidRuntime(1712):在android.a pp.ActivityThread.main(ActivityThread.java:5039)01-05 09:10:46.766:E/AndroidRuntime(1712):at java.lang.reflect.Method.invokeNative(Native Method)01-05 09:10:46.766 :E/AndroidRuntime(1712):at java.lang.reflect.Method.invoke(Method.java:511)01-05 09:10:46.766:E/AndroidRuntime(1712):at com.android.internal.os. ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:793)01-05 09:10:46.766:E/AndroidRuntime(1712):at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:560)01-05 09:10:46.766:E/AndroidRuntime(1712):at dalvik.system.NativeStart.main(Native Method)01-05 09:10:46.766:E/AndroidRuntime(1712):引起:java.lang.NullPointerException 01 -05 09:10:46.766:E/AndroidRuntime(1712):at com.example.usb_host_final_try.MainActivity.onCreate(MainActivity.java:35)01-05 09:10:46.766:E/AndroidRuntime(1712):at android .app.Activity.performCreate(Activity.java:5104)01-05 09:10:46.766:E/AndroidRuntime(1712):at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1080)01-05 09:10:46.766:E/AndroidRuntime(1712):在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2144)01-05 09:10:46.766:E/AndroidRuntime(1712):. .. 11更多01-05 09:10:49.104:I /处理(1712):发送信号.PID:1712 SIG:9

Answer 1

编辑:如果在XML中定义,则实际上不需要权限,因此下面的答案不适用.问题是NPE - 代码中不存在此类设备"deviceName".

看起来您没有获得使用USB附件的许可,如文档和本答复中所述.

在你的onCreate():

UsbManager mUsbManager = (UsbManager) getSystemService(Context.USB_SERVICE);
private static final String ACTION_USB_PERMISSION =
    "com.android.example.USB_PERMISSION";
...
mPermissionIntent = PendingIntent.getBroadcast(this, 0, new Intent(ACTION_USB_PERMISSION), 0);
IntentFilter filter = new IntentFilter(ACTION_USB_PERMISSION);
registerReceiver(mUsbReceiver, filter);

在你的Activity:

private static final String ACTION_USB_PERMISSION =
    "com.android.example.USB_PERMISSION";
private final BroadcastReceiver mUsbReceiver = new BroadcastReceiver() {

    public void onReceive(Context context, Intent intent) {
        String action = intent.getAction();
        if (ACTION_USB_PERMISSION.equals(action)) {
            synchronized (this) {
                UsbAccessory accessory = (UsbAccessory) intent.getParcelableExtra(UsbManager.EXTRA_ACCESSORY);

                if (intent.getBooleanExtra(UsbManager.EXTRA_PERMISSION_GRANTED, false)) {
                    if(accessory != null){
                        //call method to set up accessory communication
                    }
                }
                else {
                    Log.d(TAG, "permission denied for accessory " + accessory);
                }
            }
        }
    }
};

要显示获取权限的对话框:

UsbAccessory accessory;
...
mUsbManager.requestPermission(accessory, mPermissionIntent);

Answer 2

主要活动现在将变成这样，其余部分保持不变

    package com.example.usb_host_final_try;

import java.util.HashMap;
import java.util.Iterator;

import android.hardware.usb.UsbAccessory;
import android.hardware.usb.UsbDevice;
import android.hardware.usb.UsbManager;
import android.os.Build;
import android.os.Bundle;
import android.annotation.TargetApi;
import android.app.Activity;
import android.app.PendingIntent;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;
import android.view.Menu;
import android.widget.TextView;

public class MainActivity extends Activity {

    protected static final String TAG = null;

    @TargetApi(Build.VERSION_CODES.HONEYCOMB_MR1)
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        UsbManager manager = (UsbManager) getSystemService(Context.USB_SERVICE);
        HashMap<String, UsbDevice> deviceList = manager.getDeviceList();
        Iterator<UsbDevice> deviceIterator = deviceList.values().iterator();
        while(deviceIterator.hasNext()){
            UsbDevice device = deviceIterator.next();
            String s=device.getDeviceName();
            int pid= device.getProductId();
            int vid = device.getVendorId();
            TextView tv = (TextView) findViewById(R.id.textview);
            tv.setText(s+"\n"+Integer.toString(pid)+"\n"+Integer.toString(vid));
        }

    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.activity_main, menu);
        return true;
    }

}

这一切都归功于奥列格·瓦斯克维奇！