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activity_main.xml

<androidx.constraintlayout.widget.ConstraintLayout
  xmlns:android="http://schemas.android.com/apk/res/android"
  xmlns:tools="http://schemas.android.com/tools"
  xmlns:app="http://schemas.android.com/apk/res-auto"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  tools:context=".MainActivity">
  <LinearLayout
    android:orientation="vertical"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:gravity="center"
    app:layout_constraintEnd_toEndOf="parent"
    app:layout_constraintStart_toStartOf="parent"
    app:layout_constraintBottom_toBottomOf="parent"
    app:layout_constraintTop_toTopOf="parent"
  >
    <Button
      android:text="随机数"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:onClick="toRandomNumber"
      android:id="@+id/random"/>
    <Button
      android:text="日期时间"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:onClick="toDateTime"
      android:id="@+id/time"/>
    <Button
      android:text="方向传感器"
      android:layout_width="wrap_content"
      android:layout_height="wrap_content"
      android:onClick="toSensor"
      android:id="@+id/sensor"/>
  LinearLayout>

androidx.constraintlayout.widget.ConstraintLayout>

MainActivity.java

package com.weijun901.show;

import android.content.Intent;
import android.view.View;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Bundle;

public class MainActivity extends AppCompatActivity {

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

  public void toRandomNumber(View view) {
    Intent intent = new Intent(this, RandomNumber.class); // 替换为目标页面的类名
    startActivity(intent);
  }

  public void toDateTime(View view) {
    Intent intent = new Intent(this, DateTime.class); // 替换为目标页面的类名
    startActivity(intent);
  }

  public void toSensor(View view) {
    Intent intent = new Intent(this, Sensor.class); // 替换为目标页面的类名
    startActivity(intent);
  }
}