Hexo

转义字符\t 制表符 \n 换行符 \ \ 一个\ \ “ 一个” \ ‘ 一个’ 八大基本数据类型数值型：整数类型(byte，short，int，long)、浮点类型(float,double) 字符型：(char) char类型为2个字节，本质就是一个数值 布尔型：(boolean) 整数型byte 1字节 -128~127 short 2字节 int 4字节 long 长整型 8字节 出现在代码中的整数，默认为int。声明long常量需后面加L或l 浮点型float 4字节 double 8字节 出现在代码中的小数，默认为double。声明float常量需后面加F或f 字符型char 2字节，可以用来存汉字，char的本质是一个整数，输出的是unicode码对应的字符。如果非要输出一个整数，需要强制转换(int) 布尔型boolean 1字节 自动类型转换数据类型按精度大小排序char -> int -> long -> float -> double byte -> short -> int -> long -> ...

FragmentFragment的产生 什么是Fragment Fragment的使用方法MainActivity.javapackage a.b.c.fragmentbase;import android.os.Bundle;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 MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); ...

MainActivitypackage a.b.c.viewpager;import android.os.Bundle;import android.view.LayoutInflater;import android.view.View;import androidx.activity.EdgeToEdge;import androidx.appcompat.app.AppCompatActivity;import androidx.core.graphics.Insets;import androidx.core.view.ViewCompat;import androidx.core.view.WindowInsetsCompat;import androidx.viewpager.widget.ViewPager;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity { @Override protecte ...

package a.b.c.layoutparams;import android.os.Bundle;import android.view.View;import android.view.ViewGroup;import android.widget.LinearLayout;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 MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceSt ...

逐帧动画定义：把几张图片快速播放形成的一个效果 MainActivitypackage a.b.c.lele_anim;import android.graphics.drawable.AnimationDrawable;import android.os.Bundle;import android.view.View;import android.widget.RelativeLayout;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 MainActivity extends AppCompatActivity{ private boolean flag = true; @Ov ...

ListViewMainActivitypackage a.b.c.lelelistview;import android.os.Bundle;import android.util.Log;import android.view.View;import android.widget.AdapterView;import android.widget.ListView;import androidx.activity.EdgeToEdge;import androidx.appcompat.app.AppCompatActivity;import androidx.core.graphics.Insets;import androidx.core.view.ViewCompat;import androidx.core.view.WindowInsetsCompat;import java.util.ArrayList;import java.util.List;public class MainActivity extends AppCompatActivity{ p ...

LinearLayout <?xml version="1.0" encoding="utf-8"?><LinearLayout android:layout_height="match_parent" android:layout_width="match_parent" xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" > <LinearLayout android:layout_width="100dp" android:layout_height="100dp" android:background="#ff0000" /> <LinearL ...

TextView基础属性详解 <?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical" > <TextView android:layout_width="match_parent" android:layout_height="match_parent" android:id="@+id/tv_one" android:text ...

Animal类import java.time.LocalDate;public class Customer { private String name; private int visitCount; private LocalDate latestVisitDate; public Customer(String name, int visitCount, LocalDate latestVisitDate) { this.name = name; this.visitCount = visitCount; this.latestVisitDate = latestVisitDate; } @Override public String toString() { return "顾客 [name=" + name + ", visitCount=" + visitCount + ", lates ...