我正在编写一个Android应用程序，以在蓝牙热线打印机上打印文本。这是完整的代码
该应用在调试模式下工作正常，但是当我生成签名的APK并将其安装在设备上时，它根本不响应。
我尝试了在stackoverflow上建议的其他解决方案，但其中的未工作。
这是我的主要活动
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.os.AsyncTask;
import android.os.Handler;
import android.os.Message;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import com.lvrenyang.io.IOCallBack;
import java.lang.ref.WeakReference;
public class MainActivity extends AppCompatActivity {
private Handler mHandler; // Our main handler that will receive callback notifications
// #defines for identifying shared types between calling functions
private final static int REQUEST_ENABLE_BT = 1; // used to identify adding bluetooth names
private static String TAG = "MAIN_ACTIVITY";
private Activity activity;
private Button btnConnect;
private String name = "MTP-II";
private String mac_address = "02:15:44:31:49:05";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Get the activity
this.activity = this;
//Button from the XML view
btnConnect = findViewById(R.id.btnConnect);
//Start the Init Work Service Async task
new InitWorkService().execute();
//Set onClickListener for test print button
btnConnect.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
try {
//Check if name and address are set
if (name != "null" && mac_address != "null" && mac_address.contains(":")) {
if (!WorkService.workThread.isConnected()) {
WorkService.workThread.connectBt(mac_address);
//Sleep for 3 seconds
try {
Thread.sleep(3000);
} catch (Exception e) {
}
}
//Check if connected
if (WorkService.workThread.isConnected()) {
//Collect data in background Thread
new PrintData().execute();
} else {
Toast.makeText(activity, Global.toast_notconnect, Toast.LENGTH_SHORT).show();
}
} else {
Toast.makeText(activity, "Please setup printer first!", Toast.LENGTH_LONG).show();
}
}
catch(Exception e){
Log.e(TAG, e.getMessage(), e.fillInStackTrace());}
}
});
}
/**
* Background Async Task
* */
private class InitWorkService extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
protected String doInBackground(String... args){
try{
WorkService.cb = new IOCallBack() {
public void OnOpen() {
if (null != mHandler) {
Message msg = mHandler.obtainMessage(Global.MSG_IO_ONOPEN);
mHandler.sendMessage(msg);
}
}
public void OnClose() {
if (null != mHandler) {
Message msg = mHandler.obtainMessage(Global.MSG_IO_ONCLOSE);
mHandler.sendMessage(msg);
}
}
};
}
catch(Exception e){
Log.e(TAG, e.getMessage(), e.fillInStackTrace());
}
return null;
}
protected void onPostExecute(String file_url){
try {
mHandler = new MHandler(MainActivity.this);
WorkService.addHandler(mHandler);
if (null == WorkService.workThread) {
Intent intent = new Intent(activity, WorkService.class);
startService(intent);
}
}
catch (Exception e) {
Log.e(TAG, e.getMessage(), e.fillInStackTrace());
Toast.makeText(activity, "Unable to initiate the WorkService!", Toast.LENGTH_LONG).show();
}
}
}
/**
* Background Async Task
* */
class PrintData extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
}
protected String doInBackground(String... args){
try{
int nTextAlign=1;
String text = "Test message!rnrnrn";
String encoding = "UTF-8";
byte[] hdrBytes = {0x1c, 0x26, 0x1b, 0x39, 0x01};
Bundle dataAlign = new Bundle();
Bundle dataTextOut = new Bundle();
Bundle dataHdr = new Bundle();
dataHdr.putByteArray(Global.BYTESPARA1, hdrBytes);
dataHdr.putInt(Global.INTPARA1, 0);
dataHdr.putInt(Global.INTPARA2, hdrBytes.length);
dataAlign.putInt(Global.INTPARA1, nTextAlign);
dataTextOut.putString(Global.STRPARA1, text);
dataTextOut.putString(Global.STRPARA2, encoding);
WorkService.workThread.handleCmd(Global.CMD_POS_WRITE,dataHdr);
WorkService.workThread.handleCmd(Global.CMD_POS_SALIGN,dataAlign);
WorkService.workThread.handleCmd(Global.CMD_POS_STEXTOUT,dataTextOut);
}catch(Exception e){
Log.e(TAG, e.getMessage(), e.fillInStackTrace());
}
return null;
}
protected void onPostExecute(String file_url){}
}
@Override
protected void onUserLeaveHint()
{
Log.d("onUserLeaveHint","Home button pressed");
super.onUserLeaveHint();
//Unregister bluetooth receiver
try{unregisterReceiver(bluetoothReceiver);}catch(Exception e){}
//Disconnect bt connection
try{WorkService.workThread.disconnectBt();}catch(Exception e){}
// remove the handler
try{WorkService.delHandler(mHandler);}catch(Exception e){}
mHandler = null;
}
/**
* Broadcast receiver for bluetooth state changes
*/
private final BroadcastReceiver bluetoothReceiver = new BroadcastReceiver() {
@Override
public void onReceive(Context context, Intent intent)
{
final String action = intent.getAction();
if (action.equals(BluetoothAdapter.ACTION_STATE_CHANGED))
{
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,BluetoothAdapter.ERROR);
switch (state)
{
case BluetoothAdapter.STATE_OFF:
// closeConnection();//Close on going connection and disable button
Intent enableBtIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivityForResult(enableBtIntent, REQUEST_ENABLE_BT);
break;
case BluetoothAdapter.STATE_ON:
break;
}
}
}
};
private static class MHandler extends Handler {
WeakReference<MainActivity> mActivity;
MHandler(MainActivity activity) {
mActivity = new WeakReference<>(activity);
}
@Override
public void handleMessage(Message msg) {
MainActivity theActivity = mActivity.get();
switch (msg.what) {
case Global.CMD_POS_STEXTOUTRESULT:
case Global.CMD_POS_WRITERESULT: {
int result = msg.arg1;
Toast.makeText(
theActivity,
(result == 1) ? Global.toast_success
: Global.toast_fail, Toast.LENGTH_SHORT).show();
Log.v(TAG, "Result: " + result);
break;
}
}
}
}
}
您的应用显示使用蓝牙的权限吗？
在为了在应用程序中使用蓝牙功能，您必须声明两个权限。其中的第一个是蓝牙。您需要此权限来执行任何蓝牙通信，例如请求连接，接受连接和传输数据。
您必须声明的其他许可是 access_coarse_location或access_fine_location。位置许可 需要，因为蓝牙扫描可用于收集信息 关于用户的位置。此信息可能来自 用户自己的设备以及正在使用的蓝牙信标 例如商店和过境设施。
仅在签署APK时发生，似乎您必须更新UR Proguard规则，以排除打印机lib clases或类似的
应用程序不响应的一个原因是，在单击按钮的单击侦听器中，在第60行中停止主线程3秒。用以下代码替换 ongreate((方法
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Get the activity
this.activity = this;
//Button from the XML view
btnConnect = findViewById(R.id.btnConnect);
//Start the Init Work Service Async task
new InitWorkService().execute();
final ExecutorService es = Executors.newFixedThreadPool(1);
//Set onClickListener for test print button
btnConnect.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
btnConnect.setEnabled(false);
es.submit(new Runnable() {
@Override
public void run() {
connect();
}
});
}
});
}
private void connect() {
try {
//Check if name and address are set
if (name != null && mac_address != null && mac_address.contains(":")) {
if (!WorkService.workThread.isConnected()) {
WorkService.workThread.connectBt(mac_address);
//Sleep for 3 seconds
try {
Thread.sleep(3000);
} catch (Exception e) {
}
}
//Check if connected
if (WorkService.workThread.isConnected()) {
//Collect data in background Thread
new PrintData().execute();
} else {
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
Toast.makeText(activity, Global.toast_notconnect, Toast.LENGTH_SHORT).show();
}
});
}
} else {
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
Toast.makeText(activity, "Please setup printer first!", Toast.LENGTH_LONG).show();
}
});
}
} catch (Exception e) {
Log.e(TAG, e.getMessage(), e.fillInStackTrace());
}
new Handler(Looper.getMainLooper()).post(new Runnable() {
@Override
public void run() {
btnConnect.setEnabled(true);
}
});
}
现在，连接零件在新线程中执行，只有UI操作在主台上。
请注意此代码不是最佳解决方案，因为它没有考虑到活动生命周期。如果活动在螺纹入睡时重新创建活动，则仍然可以参考旧活动。但这应该是您的起点。