1 . 熟悉Android studio

基本界面

package com.example.a;

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);
    }
}

<?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">

    <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" />

小项目---飞花令

点击按钮：切按钮的标题
开始和暂停之间切换
准备候词 数组保存
开始
暂停

activity-main

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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"
    android:orientation="vertical"
    tools:context=".MainActivity">
    <!-- 文本框ctrl+/   -->

    <TextView
        android:id="@+id/tv_name"
        android:layout_width="match_parent"
        android:layout_height="250dp"
        android:background="#58c5c7"
        android:gravity="center"
        android:text="飞花令"
        android:textColor="#FFF"
        android:textSize="30sp"

        />
    <!--    按钮-->
    <Button
        android:layout_width="match_parent"
        android:layout_height="65dp"
        android:layout_marginLeft="50dp"
        android:layout_marginTop="100dp"
        android:layout_marginRight="50dp"
        android:background="#D65489"
        android:onClick="start"
        android:text="开始"
        android:textColor="#FFF"
        android:textSize="20sp"

        />
</LinearLayout>

MainActivity

package com.example.a;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;

import java.sql.Time;
import java.util.Random;
import java.util.Timer;
import java.util.TimerTask;

public class MainActivity extends AppCompatActivity {
  String[] names = new  String[]{"花","酒","秋风","草","桃花","燕子","雁杜","鹃雨"};
  Timer timer;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
    }

    //按钮的点击事件
    public void start(View view) {
        //  System.out.println("点击了");
        //将view转换成button
        Button btn = (Button) view;
        //获取当前的标题
        String title = btn.getText().toString();
        //判断按钮的标题
        if (title.equals("开始")) {
            //设置为暂停
            btn.setText("暂停");
            timer = new Timer();
            timer.schedule(new TimerTask() {
                @Override
                public void run() {

                }
            },0,100);
        } else {
            //设置为暂停
            btn.setText("开始");
            timer.cancel();//关闭定时器
        }
        peom();
    }
    public void  peom(){
        //产生一个随机数
        Random random = new Random();
        int index = Math.abs(random.nextInt()) % names.length;
        //从数组里面取出这个词
        String name = names[index];
        //将名字框显示到文本
        TextView tv = findViewById(R.id.tv_name);
        tv.setText(name);
    }
}

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