3.1.6 checkbox控件

3.1.6 checkbox控件

<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">

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="Hello World!"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

</androidx.constraintlayout.widget.ConstraintLayout>

（复选框，当点击发羽毛球，篮球，乒乓球的时候，下面的txexview控件显示选择了什么？）

<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">

<TextView
    android:id="@+id/textViewResult"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="您选择的兴趣爱好为："
    app:layout_constraintBottom_toTopOf="@+id/checkBoxBadminton"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toTopOf="parent" />

<CheckBox
    android:id="@+id/checkBoxBadminton"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="羽毛球"
    app:layout_constraintBottom_toTopOf="@+id/checkBoxBasketball"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@id/textViewResult" />

<CheckBox
    android:id="@+id/checkBoxBasketball"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="篮球"
    app:layout_constraintBottom_toTopOf="@+id/checkBoxTableTennis"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@id/checkBoxBadminton" />

<CheckBox
    android:id="@+id/checkBoxTableTennis"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:text="乒乓球"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintLeft_toLeftOf="parent"
    app:layout_constraintRight_toRightOf="parent"
    app:layout_constraintTop_toBottomOf="@id/checkBoxBasketball" />

</androidx.constraintlayout.widget.ConstraintLayout>

import android.os.Bundle;
import android.view.View;
import android.widget.CheckBox;
import android.widget.TextView;
import androidx.appcompat.app.AppCompatActivity;

public class MainActivity extends AppCompatActivity {

private TextView textViewResult;
private CheckBox checkBoxBadminton, checkBoxBasketball, checkBoxTableTennis;

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

    textViewResult = findViewById(R.id.textViewResult);
    checkBoxBadminton = findViewById(R.id.checkBoxBadminton);
    checkBoxBasketball = findViewById(R.id.checkBoxBasketball);
    checkBoxTableTennis = findViewById(R.id.checkBoxTableTennis);

    checkBoxBadminton.setOnCheckedChangeListener((buttonView, isChecked) -> updateTextView());
    checkBoxBasketball.setOnCheckedChangeListener((buttonView, isChecked) -> updateTextView());
    checkBoxTableTennis.setOnCheckedChangeListener((buttonView, isChecked) -> updateTextView());
}

private void updateTextView() {
    StringBuilder selectedHobbies = new StringBuilder("您选择的兴趣爱好为：");
    if (checkBoxBadminton.isChecked()) {
        selectedHobbies.append("羽毛球 ");
    }
    if (checkBoxBasketball.isChecked()) {
        selectedHobbies.append("篮球 ");
    }
    if (checkBoxTableTennis.isChecked()) {
        selectedHobbies.append("乒乓球 ");
    }
    textViewResult.setText(selectedHobbies.toString().trim());
}

}