适用于Arduino的带有HC-05的Android控制器没有有用的错误

Question

我正在尝试从arduino到蓝牙电话进行温度显示，但我不明白为什么它不起作用

我试图对代码的某些部分进行注释，有时它不能与某件事一起使用，有时却可以工作，这很奇怪

activity1 java（主要）

package it.aletinti.apkduino;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;

import java.util.ArrayList;
import java.util.List;
import java.util.Set;

public class activity1 extends AppCompatActivity {

    BluetoothAdapter btAdapter = BluetoothAdapter.getDefaultAdapter();
    ListView btDeviceList;
    String btDevice;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity1);

        Intent btEnable = new Intent(BluetoothAdapter.ACTION_REQUEST_ENABLE);
        startActivityForResult(btEnable, 1);

        btDeviceList = findViewById(R.id.btDeviceList);

        Set<BluetoothDevice> pairedDevices = btAdapter.getBondedDevices();
        List<String> ArrayList = new ArrayList();
        for(BluetoothDevice btAdapter : pairedDevices) ArrayList.add(btAdapter.getName());
        final ArrayAdapter btDeviceArrayAdapter = new ArrayAdapter(this, android.R.layout.simple_list_item_1, ArrayList);
        btDeviceList.setAdapter(btDeviceArrayAdapter);

        btDeviceList.setOnItemClickListener(new AdapterView.OnItemClickListener(){
            @Override
            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
                btDevice = (btDeviceArrayAdapter.getItem(position)).toString();
                activity2();
            }
        });
    }

    public void activity2(){
        Intent NextActivity = new Intent(this, activity2.class);
        NextActivity.putExtra("btDevice", btDevice);
        startActivity(NextActivity);
    }
}

activity1 xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    android:background="@color/dark"
    tools:context=".activity1">

    <ListView
        android:id="@+id/btDeviceList"
        android:layout_width="339dp"
        android:layout_height="629dp"
        android:layout_marginTop="60dp"
        android:layout_marginBottom="16dp"
        android:textColor="@color/white"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:layout_constraintVertical_bias="0.0" />

    <TextView
        android:id="@+id/selectTextView"
        android:layout_width="175dp"
        android:layout_height="20dp"
        android:layout_marginStart="16dp"
        android:layout_marginTop="32dp"
        android:layout_marginEnd="16dp"
        android:layout_marginBottom="16dp"
        android:text="Select a device to connect"
        android:textColor="@color/white"
        app:layout_constraintBottom_toTopOf="@+id/btDeviceList"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>

activity2 java（崩溃或未运行）

package it.aletinti.apkduino;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.SeekBar;
import android.widget.TextView;

import java.util.UUID;
import java.util.concurrent.TimeUnit;

public class activity2 extends AppCompatActivity {

    private static final UUID btUUID = UUID.fromString("00001101-0000-1000-8000-00805F9B34FB");
    ;
    TextView stateText, btText, adText, maxText, minText;
    SeekBar maxBar, minBar;
    int minTemp, maxTemp;
    BluetoothSocket btSocket = null;
    Button updateButton;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity2);

        maxBar = this.findViewById(R.id.maxBar);
        minBar = this.findViewById(R.id.minBar);
        updateButton = this.findViewById(R.id.updateButton);
        maxText = this.findViewById(R.id.maxText);
        minText = this.findViewById(R.id.minText);
        stateText = this.findViewById(R.id.stateText);

        maxBar.setProgress(3);
        minBar.setProgress(3);

        final BluetoothAdapter btAdapter = BluetoothAdapter.getDefaultAdapter();

        Bundle getbtDevice = getIntent().getExtras();
        String btDeviceName = getbtDevice.getString("btDevice");

        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    BluetoothDevice btDevice = btAdapter.getRemoteDevice(/*btDeviceName*/"AB:90:78:57:C2:5A" /*USING MAC FOR MORE SURE PAIR ONLY IN DEBUG*/);
                    btSocket = btDevice.createRfcommSocketToServiceRecord(btUUID);
                    btSocket.connect();
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    while (!isDestroyed()/*or true*/) {
                        byte[] buffer = new byte[1024];
                        int bytes = btSocket.getInputStream().read(buffer, 0, buffer.length);
                        String readMessage = new String(buffer, 0, bytes);
                        System.out.println(readMessage);
                        final String t = readMessage.split("/")[0];
                        final String h = readMessage.split("/")[1];
                        runOnUiThread(new Runnable() {
                            @Override
                            public void run() {
                                stateText.setText("Temperature: " + t + "°" + "\nHumidity: " + h + "%");
                            }
                        });
                    }
                } catch (Exception e) {
                    e.printStackTrace();
                }
            }
        }).start();

        new Thread(new Runnable() {
            @Override
            public void run() {
                while (true) {
                    maxTemp = 24 + maxBar.getProgress();
                    minTemp = 20 - minBar.getProgress();
                    runOnUiThread(new Runnable() {
                        @Override
                        public void run() {
                            minText.setText("Min: " + minTemp);
                            maxText.setText("Max: " + maxTemp);
                        }
                    });
                }
            }
        }).start();
    }
}

activity2 xml

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.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"
    android:background="@color/dark"
    tools:context=".activity2">

    <TextView
        android:id="@+id/stateText"
        android:layout_width="298dp"
        android:layout_height="166dp"
        android:layout_marginStart="32dp"
        android:layout_marginTop="96dp"
        android:layout_marginEnd="32dp"
        android:gravity="center"
        android:text="Temperature:\nHumidity:"
        android:textColor="@color/white"
        android:textSize="30dp"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.489"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent" />

    <TextView
        android:id="@+id/maxText"
        android:layout_width="136dp"
        android:layout_height="19dp"
        android:layout_marginBottom="20dp"
        android:gravity="center"
        android:text="MAX"
        android:textColor="@color/white"
        app:layout_constraintBottom_toTopOf="@+id/maxBar"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <Button
        android:id="@+id/updateButton"
        android:layout_width="253dp"
        android:layout_height="37dp"
        android:layout_marginBottom="50dp"
        android:background="@color/arduino"
        android:text="Update"
        android:textColor="@color/white"
        app:layout_constraintBottom_toBottomOf="parent"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <SeekBar
        android:id="@+id/minBar"
        android:layout_width="250dp"
        android:layout_height="25dp"
        android:layout_marginBottom="50dp"
        android:layoutDirection="rtl"
        android:max="8"
        android:min="0"
        app:layout_constraintBottom_toTopOf="@+id/updateButton"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <SeekBar
        android:id="@+id/maxBar"
        android:layout_width="250dp"
        android:layout_height="25dp"
        android:layout_marginBottom="40dp"
        android:layoutDirection="ltr"
        android:max="8"
        android:min="0"
        app:layout_constraintBottom_toTopOf="@+id/minText"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent" />

    <TextView
        android:id="@+id/minText"
        android:layout_width="136dp"
        android:layout_height="19dp"
        android:layout_marginBottom="20dp"
        android:gravity="center"
        android:text="MIN"
        android:textColor="@color/white"
        app:layout_constraintBottom_toTopOf="@+id/minBar"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintHorizontal_bias="0.498"
        app:layout_constraintStart_toStartOf="parent" />
</android.support.constraint.ConstraintLayout>

错误

Process: it.aletinti.apkduino, PID: 26745
    java.lang.NullPointerException: Attempt to invoke virtual method 'int android.text.Layout.getWidth()' on a null object reference
        at android.widget.TextView.onMeasure(TextView.java:8637)
        at android.support.v7.widget.AppCompatTextView.onMeasure(AppCompatTextView.java:501)
        at android.view.View.measure(View.java:23181)
        at android.support.constraint.ConstraintLayout.internalMeasureChildren(ConstraintLayout.java:1227)
        at android.support.constraint.ConstraintLayout.onMeasure(ConstraintLayout.java:1572)
        at android.view.View.measure(View.java:23181)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.support.v7.widget.ContentFrameLayout.onMeasure(ContentFrameLayout.java:143)
        at android.view.View.measure(View.java:23181)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.support.v7.widget.ActionBarOverlayLayout.onMeasure(ActionBarOverlayLayout.java:401)
        at android.view.View.measure(View.java:23181)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at android.view.View.measure(View.java:23181)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.LinearLayout.measureChildBeforeLayout(LinearLayout.java:1535)
        at android.widget.LinearLayout.measureVertical(LinearLayout.java:825)
        at android.widget.LinearLayout.onMeasure(LinearLayout.java:704)
        at android.view.View.measure(View.java:23181)
        at android.view.ViewGroup.measureChildWithMargins(ViewGroup.java:6749)
        at android.widget.FrameLayout.onMeasure(FrameLayout.java:185)
        at com.android.internal.policy.DecorView.onMeasure(DecorView.java:716)
        at android.view.View.measure(View.java:23181)
        at android.view.ViewRootImpl.performMeasure(ViewRootImpl.java:2727)
        at android.view.ViewRootImpl.measureHierarchy(ViewRootImpl.java:1580)
        at android.view.ViewRootImpl.performTraversals(ViewRootImpl.java:1864)
        at android.view.ViewRootImpl.doTraversal(ViewRootImpl.java:1468)
        at android.view.ViewRootImpl$TraversalRunnable.run(ViewRootImpl.java:7208)
        at android.view.Choreographer$CallbackRecord.run(Choreographer.java:1004)
        at android.view.Choreographer.doCallbacks(Choreographer.java:816)
        at android.view.Choreographer.doFrame(Choreographer.java:751)
        at android.view.Choreographer$FrameDisplayEventReceiver.run(Choreographer.java:990)
        at android.os.Handler.handleCallback(Handler.java:873)
        at android.os.Handler.dispatchMessage(Handler.java:99)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:6694)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.RuntimeInit$MethodAndArgsCaller.run(RuntimeInit.java:493)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:858)

有时会运行但不加载温度，其他时候如果不输入活动1就会崩溃，而其他时候我输入活动2则会崩溃。我是android的新手，但我不明白为什么此代码会崩溃！！！

更新：现在不会崩溃，但不会读写信号，而是链接蓝牙