设置文本大小

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_height="match_parent"
    android:layout_width="match_parent"
    android:orientation="vertical">

    <TextView
        android:id="@+id/tv_px"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="PX：你好，世界！"
        android:textSize="30px"/>

    <TextView
        android:id="@+id/tv_dp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="DP：你好，世界！"
        android:textSize="30dp"/>

    <TextView
        android:id="@+id/tv_sp"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="SP：你好，世界！"
        android:textSize="30sp"/>

</LinearLayout>

package com.example.chapter003;

import android.os.Bundle;
import android.widget.TextView;

import androidx.activity.EdgeToEdge;
import androidx.appcompat.app.AppCompatActivity;
import androidx.core.graphics.Insets;
import androidx.core.view.ViewCompat;
import androidx.core.view.WindowInsetsCompat;

public class TextSizeActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_text_size);
        TextView tv_hello = findViewById(R.id.tv_px);
        //tv_hello.setText(R.string.app_name);
        tv_hello.setTextSize(30);
    }
}