如何解决数据显示在 logcat 上，但我无法在我的 android 上显示它
所以，我试图从连接到我的 arduino Uno 的 HC05 接收数据，从温度传感器 DHT11 接收值。我制作了一个应用程序，所以我可以获得这些值，但它们只显示在 logcat 上，而不显示在我的 android 屏幕上。
这是我的 ShowInfoActivity，我在其中激活 BT 并允许我显示不同的 BT 设备。
package com.example.temperaturaehumidade;
import android.Manifest;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.broadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Build;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Button;
import android.widget.EditText;
import android.widget.ListView;
import android.widget.TextView;
import android.widget.Toast;
import androidx.annotation.Nullable;
import androidx.appcompat.app.AppCompatActivity;
import java.util.ArrayList;
import java.util.UUID;
public class ShowInfoActivity extends AppCompatActivity{
private static final String TAG = "ShowInfoActivity";
private Button btndiscoverability;
private Button btnSearch;
private Button btnONOFF;
private Button btnConnect;
private ListView listView;
BluetoothAdapter mBluetoothAdapter;
Button btnEnabledisable_discoverable;
BluetoothConnection mBluetoothConnection;
TextView etSend;
private static final UUID MY_UUID_INSECURE =
UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
BluetoothDevice mBTDevice;
public ArrayList<BluetoothDevice> mBTDevices = new ArrayList<>();
public Devicelistadapter mDevicelistadapter;
ListView lvNewDevices;
// Create a broadcastReceiver for ACTION_FOUND
private final broadcastReceiver mbroadcastReceiver1 = new broadcastReceiver() {
public void onReceive(Context context,Intent intent) {
String action = intent.getAction();
// When discovery finds a device
if (action.equals(mBluetoothAdapter.ACTION_STATE_CHANGED)) {
final int state = intent.getIntExtra(BluetoothAdapter.EXTRA_STATE,mBluetoothAdapter.ERROR);
switch (state) {
case BluetoothAdapter.STATE_OFF:
Log.d(TAG,"onReceive: STATE OFF");
break;
case BluetoothAdapter.STATE_TURNING_OFF:
Log.d(TAG,"mbroadcastReceiver1: STATE TURNING OFF");
break;
case BluetoothAdapter.STATE_ON:
Log.d(TAG,"mbroadcastReceiver1: STATE ON");
break;
case BluetoothAdapter.STATE_TURNING_ON:
Log.d(TAG,"mbroadcastReceiver1: STATE TURNING ON");
break;
}
}
}
};
/**
* broadcast Receiver for changes made to bluetooth states such as:
* 1) discoverability mode on/off or expire.
*/
private final broadcastReceiver mbroadcastReceiver2 = new broadcastReceiver() {
@Override
public void onReceive(Context context,Intent intent) {
final String action = intent.getAction();
if (action.equals(BluetoothAdapter.ACTION_SCAN_MODE_CHANGED)) {
int mode = intent.getIntExtra(BluetoothAdapter.EXTRA_SCAN_MODE,BluetoothAdapter.ERROR);
switch (mode) {
//Device is in discoverable Mode
case BluetoothAdapter.SCAN_MODE_CONNECTABLE_disCOVERABLE:
Log.d(TAG,"mbroadcastReceiver2: discoverability Enabled.");
break;
//Device not in discoverable mode
case BluetoothAdapter.SCAN_MODE_CONNECTABLE:
Log.d(TAG,"mbroadcastReceiver2: discoverability disabled. Able to receive connections.");
break;
case BluetoothAdapter.SCAN_MODE_NONE:
Log.d(TAG,"mbroadcastReceiver2: discoverability disabled. Not able to receive connections.");
break;
case BluetoothAdapter.STATE_CONNECTING:
Log.d(TAG,"mbroadcastReceiver2: Connecting....");
break;
case BluetoothAdapter.STATE_CONNECTED:
Log.d(TAG,"mbroadcastReceiver2: Connected.");
break;
}
}
}
};
/**
* broadcast Receiver for listing devices that are not yet paired
* -Executed by btndiscover() method.
*/
private broadcastReceiver mbroadcastReceiver3 = new broadcastReceiver() {
@Override
public void onReceive(Context context,Intent intent) {
final String action = intent.getAction();
Log.d(TAG,"onReceive: ACTION FOUND.");
if (action.equals(BluetoothDevice.ACTION_FOUND)) {
BluetoothDevice device = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
mBTDevices.add(device);
Log.d(TAG,"onReceive: " + device.getName() + ": " + device.getAddress());
mDevicelistadapter = new Devicelistadapter(context,R.layout.list_item,mBTDevices);
lvNewDevices.setAdapter(mDevicelistadapter);
}
}
};
/**
* broadcast Receiver that detects bond state changes (Pairing status changes)
*/
private final broadcastReceiver mbroadcastReceiver4 = new broadcastReceiver() {
@Override
public void onReceive(Context context,Intent intent) {
final String action = intent.getAction();
if (action.equals(BluetoothDevice.ACTION_BOND_STATE_CHANGED)) {
BluetoothDevice mDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
//3 cases:
//case1: bonded already
if (mDevice.getBondState() == BluetoothDevice.BOND_BONDED) {
Log.d(TAG,"broadcastReceiver: BOND_BONDED.");
//inside broadcastReceiver4
mBTDevice = mDevice;
}
//case2: creating a bone
if (mDevice.getBondState() == BluetoothDevice.BOND_BONDING) {
Log.d(TAG,"broadcastReceiver: BOND_BONDING.");
}
//case3: breaking a bond
if (mDevice.getBondState() == BluetoothDevice.BOND_NONE) {
Log.d(TAG,"broadcastReceiver: BOND_NONE.");
}
}
}
};
@Override
protected void onDestroy() {
Log.d(TAG,"onDestroy: called.");
super.onDestroy();
unregisterReceiver(mbroadcastReceiver1);
unregisterReceiver(mbroadcastReceiver2);
unregisterReceiver(mbroadcastReceiver3);
unregisterReceiver(mbroadcastReceiver4);
}
@Override
protected void onCreate(@Nullable Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_info);
btnConnect=findViewById(R.id.id_connect);
btndiscoverability = findViewById(R.id.id_discoverability);
btnONOFF = findViewById(R.id.id_ONOFF);
btnSearch = findViewById(R.id.id_search);
lvNewDevices = (ListView) findViewById(R.id.lvNewDevices);
etSend = (TextView) findViewById(R.id.txtReceive);
mBTDevices = new ArrayList<>();
//broadcasts when bond state changes (ie:pairing)
IntentFilter filter = new IntentFilter(BluetoothDevice.ACTION_BOND_STATE_CHANGED);
registerReceiver(mbroadcastReceiver4,filter);
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
lvNewDevices.setonItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent,View view,int i,long id) {
//first cancel discovery because its very memory intensive.
mBluetoothAdapter.canceldiscovery();
Log.d(TAG,"onItemClick: You Clicked on a device.");
String deviceName = mBTDevices.get(i).getName();
String deviceAddress = mBTDevices.get(i).getAddress();
Log.d(TAG,"onItemClick: deviceName = " + deviceName);
Log.d(TAG,"onItemClick: deviceAddress = " + deviceAddress);
//create the bond.
//NOTE: Requires API 17+? I think this is JellyBean
if(Build.VERSION.SDK_INT > Build.VERSION_CODES.JELLY_BEAN_MR2){
Log.d(TAG,"Trying to pair with " + deviceName);
mBTDevices.get(i).createBond();
mBTDevice = mBTDevices.get(i);
mBluetoothConnection = new BluetoothConnection(ShowInfoActivity.this);
}
}
});
btnConnect.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
startConnection();
}
});
btnONOFF.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d(TAG,"onClick: enabling/disabling bluetooth.");
enabledisableBT();
}
});
btndiscoverability.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d(TAG,"btnEnabledisable_discoverable: Making device discoverable for 300 seconds.");
enabledisablediscoverability();
}
});
btnSearch.setonClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Log.d(TAG,"btndiscover: Looking for unpaired devices.");
enablediscover();
}
});
}
//create method for starting connection
//***remember the conncction will fail and app will crash if you haven't paired first
public void startConnection(){
startBTConnection(mBTDevice,MY_UUID_INSECURE);
}
/**
* starting chat service method
*/
public void startBTConnection(BluetoothDevice device,UUID uuid){
Log.d(TAG,"startBTConnection: Initializing RFCOM Bluetooth Connection.");
mBluetoothConnection.startClient(device,uuid);
}
public void enabledisableBT() {
if (mBluetoothAdapter == null) {
Log.d(TAG,"enabledisableBT: Does not have BT capabilities.");
}
if (!mBluetoothAdapter.isEnabled()) {
Log.d(TAG,"enabledisableBT: enabling BT.");
Intent enableBTIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
startActivity(enableBTIntent);
IntentFilter BTIntent = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mbroadcastReceiver1,BTIntent);
}
if (mBluetoothAdapter.isEnabled()) {
Log.d(TAG,"enabledisableBT: disabling BT.");
mBluetoothAdapter.disable();
IntentFilter BTIntent = new IntentFilter(BluetoothAdapter.ACTION_STATE_CHANGED);
registerReceiver(mbroadcastReceiver1,BTIntent);
}
}
public void enabledisablediscoverability() {
Intent discoverableIntent = new Intent(BluetoothAdapter.ACTION_REQUEST_disCOVERABLE);
discoverableIntent.putExtra(BluetoothAdapter.EXTRA_disCOVERABLE_DURATION,300);
startActivity(discoverableIntent);
IntentFilter intentFilter = new IntentFilter(mBluetoothAdapter.ACTION_SCAN_MODE_CHANGED);
registerReceiver(mbroadcastReceiver2,intentFilter);
}
public void enablediscover() {
if (mBluetoothAdapter.isdiscovering()) {
mBluetoothAdapter.canceldiscovery();
Log.d(TAG,"btndiscover: Canceling discovery.");
//check BT permissions in manifest
checkBTPermissions();
mBluetoothAdapter.startdiscovery();
IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mbroadcastReceiver3,discoverDevicesIntent);
}
if (!mBluetoothAdapter.isdiscovering()) {
//check BT permissions in manifest
checkBTPermissions();
mBluetoothAdapter.startdiscovery();
IntentFilter discoverDevicesIntent = new IntentFilter(BluetoothDevice.ACTION_FOUND);
registerReceiver(mbroadcastReceiver3,discoverDevicesIntent);
}
}
/**
* This method is required for all devices running API23+
* Android must programmatically check the permissions for bluetooth. Putting the proper permissions
* in the manifest is not enough.
* <p>
* NOTE: This will only execute on versions > LOLLIPOP because it is not needed otherwise.
*/
private void checkBTPermissions() {
if (Build.VERSION.SDK_INT > Build.VERSION_CODES.LOLLIPOP) {
int permissionCheck = this.checkSelfPermission("Manifest.permission.ACCESS_FINE_LOCATION");
permissionCheck += this.checkSelfPermission("Manifest.permission.ACCESS_COARSE_LOCATION");
if (permissionCheck != 0) {
this.requestPermissions(new String[]{Manifest.permission.ACCESS_FINE_LOCATION,Manifest.permission.ACCESS_COARSE_LOCATION},1001); //Any number
}
} else {
Log.d(TAG,"checkBTPermissions: No need to check permissions. SDK version < LOLLIPOP.");
}
}
}```
蓝牙连接
package com.example.temperaturaehumidade;
import android.app.ProgressDialog;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothServerSocket;
import android.bluetooth.BluetoothSocket;
import android.content.Context;
import android.util.Log;
import android.widget.TextView;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.nio.charset.Charset;
import java.util.UUID;
/**
* Created by User on 12/21/2016.
*/
public class BluetoothConnection {
private static final String TAG = "BluetoothConnectionServ";
private static final String appName = "MYAPP";
private static final UUID MY_UUID_INSECURE =
UUID.fromString("00001101-0000-1000-8000-00805f9b34fb");
private final BluetoothAdapter mBluetoothAdapter;
Context mContext;
private AcceptThread mInsecureAcceptThread;
private ConnectThread mConnectThread;
private TextView mTxtReceive;
private BluetoothDevice mmDevice;
private UUID deviceUUID;
ProgressDialog mProgressDialog;
private ConnectedThread mConnectedThread;
public BluetoothConnection(Context context) {
mContext = context;
mBluetoothAdapter = BluetoothAdapter.getDefaultAdapter();
start();
}
Finally the ConnectedThread which is responsible for maintaining the BTConnection,Sending the data,and
receiving incoming data through input/output streams respectively.
**/
private class ConnectedThread extends Thread {
private final BluetoothSocket mmSocket;
private final InputStream mmInStream;
private final OutputStream mmOutStream;
private class ReadInput implements Runnable {
private boolean bStop = false;
private Thread t;
public Readinput() {
t = new Thread(this,"Input Thread");
t.start();
}
public boolean isRunning() {
return t.isAlive();
}
@Override
public void run() {
InputStream inputStream;
try {
inputStream = mmSocket.getInputStream();
while (!bStop) {
byte[] buffer = new byte[256];
if (inputStream.available() > 0) {
inputStream.read(buffer);
int i = 0;
/*
* This is needed because new String(buffer) is taking the entire buffer i.e. 256 chars on Android 2.3.4 http://stackoverflow.com/a/8843462/1287554
*/
for (i = 0; i < buffer.length && buffer[i] != 0; i++) {
}
final String strInput = new String(buffer,i);
/*
* If checked then receive text,better design would probably be to stop thread if unchecked and free resources,but this is a quick fix
*/
}
Thread.sleep(500);
}
} catch (IOException e) {
// Todo Auto-generated catch block
e.printstacktrace();
} catch (InterruptedException e) {
// Todo Auto-generated catch block
e.printstacktrace();
}
}
public void stop() {
bStop = true;
}
}
public ConnectedThread(BluetoothSocket socket) {
Log.d(TAG,"ConnectedThread: Starting.");
mmSocket = socket;
InputStream tmpIn = null;
OutputStream tmpOut = null;
//dismiss the progressdialog when connection is established
try{
mProgressDialog.dismiss();
}catch (NullPointerException e){
e.printstacktrace();
}
try {
tmpIn = mmSocket.getInputStream();
tmpOut = mmSocket.getoutputStream();
} catch (IOException e) {
e.printstacktrace();
}
mmInStream = tmpIn;
mmOutStream = tmpOut;
}
public void run(){
byte[] buffer = new byte[1024]; // buffer store for the stream
int bytes; // bytes returned from read()
// Keep listening to the InputStream until an exception occurs
while (true) {
// Read from the InputStream
try {
bytes = mmInStream.read(buffer);
String incomingMessage = new String(buffer,bytes);
Log.d(TAG,"InputStream: " + incomingMessage);
} catch (IOException e) {
Log.e(TAG,"write: Error reading Input Stream. " + e.getMessage() );
break;
}
}
}
//Call this from the main activity to send data to the remote device
public void write(byte[] bytes) {
String text = new String(bytes,Charset.defaultCharset());
Log.d(TAG,"write: Writing to outputstream: " + text);
try {
mmOutStream.write(bytes);
} catch (IOException e) {
Log.e(TAG,"write: Error writing to output stream. " + e.getMessage() );
}
}
/* Call this from the main activity to shutdown the connection */
public void cancel() {
try {
mmSocket.close();
} catch (IOException e) { }
}
}
private void connected(BluetoothSocket mmSocket,BluetoothDevice mmDevice) {
Log.d(TAG,"connected: Starting.");
// Start the thread to manage the connection and perform transmissions
mConnectedThread = new ConnectedThread(mmSocket);
mConnectedThread.start();
}
/**
* Write to the ConnectedThread in an unsynchronized manner
*
* @param out The bytes to write
* @see ConnectedThread#write(byte[])
*/
public void write(byte[] out) {
// Create temporary object
ConnectedThread r;
// Synchronize a copy of the ConnectedThread
Log.d(TAG,"write: Write Called.");
//perform the write
mConnectedThread.write(out);
}
}
XML 文件：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="@color/black">
<Button
android:id="@+id/id_ONOFF"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:gravity="center_vertical|center_horizontal"
android:hint="ON/OFF"
android:textColorHint="@color/white" />
<Button
android:id="@+id/id_discoverability"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="discoverability"
android:layout_margin="20dp"
android:gravity="center_vertical|center_horizontal"
android:textColorHint="@color/white"/>
<Button
android:id="@+id/id_search"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="Search"
android:layout_margin="20dp"
android:gravity="center_vertical|center_horizontal"
android:textColorHint="@color/white"/>
<Button
android:id="@+id/id_connect"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_margin="20dp"
android:gravity="center_vertical|center_horizontal"
android:hint="Connect"
android:textColorHint="@color/white" />
<ListView
android:layout_below="@id/id_connect"
android:layout_width="match_parent"
android:layout_height="150dp"
android:id="@+id/lvNewDevices"/>
<TextView
android:id="@+id/txtReceive"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#eeeeee"
android:hint="Message shows up here ..." />
</LinearLayout>
而且这些值出现在 logcat 上而不是 android 屏幕上，有人可以帮助我吗？万分感谢。为了您的信息，我关注了这个家伙关于如何设置蓝牙连接的 YouTube 视频https://www.youtube.com/watch?v=y8R2C86BIUc&list=PLgCYzUzKIBE8KHMzpp6JITZ2JxTgWqDH2
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