Android studio 按键控制虚拟LED

一、activity_main.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<androidx.constraintlayout.widget.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"
    tools:context=".MainActivity">

    <ImageView
        android:id="@+id/Lamp"
        android:layout_width="80dp"
        android:layout_height="80dp"
        android:layout_marginTop="100dp"
        android:visibility="visible"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toTopOf="parent"
        app:srcCompat="@android:drawable/presence_online" />

    <Button
        android:id="@+id/button"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_marginTop="200dp"
        android:text="关灯"
        app:layout_constraintEnd_toEndOf="parent"
        app:layout_constraintStart_toStartOf="parent"
        app:layout_constraintTop_toBottomOf="@+id/Lamp" />


</androidx.constraintlayout.widget.ConstraintLayout>

二、MainActivity.java代码：

package com.example.third;

import androidx.appcompat.app.AppCompatActivity;

import android.graphics.Color;
import android.media.Image;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;

public class MainActivity extends AppCompatActivity implements View.OnClickListener {
    ImageView iv1;
    Button bnt1;

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

        bnt1 =findViewById(R.id.button);
        iv1 = this.findViewById(R.id.Lamp);
        iv1.setColorFilter(Color.RED);
        bnt1.setOnClickListener(this);
    }

    @Override
    public void onClick(View view) {
        if(bnt1.getText().toString().equals("关灯")){
            bnt1.setText("开灯");
            iv1.setColorFilter(Color.GRAY);
            //iv1.setVisibility(View.INVISIBLE);
        }else if(bnt1.getText().toString().equals(("开灯"))){
            //iv1.setVisibility(View.VISIBLE);
            iv1.setColorFilter(Color.RED);
            bnt1.setText("关灯");
        }
    }
}

三、AndroidManifest.xml代码：

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools">

    <application
        android:allowBackup="true"
        android:dataExtractionRules="@xml/data_extraction_rules"
        android:fullBackupContent="@xml/backup_rules"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:roundIcon="@mipmap/ic_launcher_round"
        android:supportsRtl="true"
        android:theme="@style/Theme.Third"
        tools:targetApi="31">
        <activity
            android:name=".MainActivity"
            android:exported="true"
            android:label="Key control virtual LED">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>

            <meta-data
                android:name="android.app.lib_name"
                android:value="" />
        </activity>
    </application>

</manifest>

四、运行效果：