这里是用线性布局实现的计算器,为防止以后再回顾知识代码找不到,特将代码贴在这里:
xml文件的布局代码:
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<? 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" > < EditText android:id = "@+id/et_input" android:layout_width = "match_parent" android:layout_height = "100dp" android:paddingBottom = "5dp" android:paddingRight = "5dp" android:textSize = "50sp" android:gravity = "right" android:textColor = "#00ff00" /> < LinearLayout android:layout_width = "fill_parent" android:layout_height = "wrap_content" android:layout_marginTop = "30dp" android:orientation = "horizontal" android:gravity = "center_horizontal" > < Button android:id = "@+id/btn_clr" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "C" android:textSize = "30sp" android:paddingRight = "15sp" android:paddingBottom = "15sp" android:textColor = "#ff0000" /> < Button android:id = "@+id/btn_del" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "Ba" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_add" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "+" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_sub" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "-" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> </ LinearLayout > < LinearLayout android:layout_width = "fill_parent" android:layout_height = "wrap_content" android:layout_marginTop = "10dp" android:orientation = "horizontal" android:gravity = "center_horizontal" > < Button android:id = "@+id/btn_7" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "7" android:textSize = "30sp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_8" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "8" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_9" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "9" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_mul" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "×" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> </ LinearLayout > < LinearLayout android:layout_width = "fill_parent" android:layout_height = "wrap_content" android:layout_marginTop = "10dp" android:orientation = "horizontal" android:gravity = "center_horizontal" > < Button android:id = "@+id/btn_4" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "4" android:textSize = "30sp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_5" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "5" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_6" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "6" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:id = "@+id/btn_div" android:layout_width = "80dp" android:layout_height = "80dp" android:text = "÷" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> </ LinearLayout > < LinearLayout android:layout_width = "fill_parent" android:layout_height = "wrap_content" android:orientation = "horizontal" android:layout_marginTop = "10dp" android:gravity = "center_horizontal" > < LinearLayout android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:orientation = "vertical" > < LinearLayout android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:orientation = "horizontal" > < Button android:layout_width = "80dp" android:layout_height = "80dp" android:id = "@+id/btn_1" android:text = "1" android:textSize = "30sp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:layout_width = "80dp" android:layout_height = "80dp" android:id = "@+id/btn_2" android:text = "2" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:layout_width = "80dp" android:layout_height = "80dp" android:id = "@+id/btn_3" android:text = "3" android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> </ LinearLayout > < LinearLayout android:layout_width = "wrap_content" android:layout_height = "wrap_content" android:orientation = "horizontal" android:layout_marginTop = "10dp" > < Button android:layout_width = "170dp" android:layout_height = "80dp" android:id = "@+id/btn_0" android:text = "0" android:textSize = "30sp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> < Button android:layout_width = "80dp" android:layout_height = "80dp" android:id = "@+id/btn_pt" android:text = "." android:textSize = "30sp" android:layout_marginLeft = "10dp" android:paddingRight = "15sp" android:paddingBottom = "15sp" /> </ LinearLayout > </ LinearLayout > < Button android:id = "@+id/btn_eq" android:layout_width = "80dp" android:layout_height = "170dp" android:layout_marginLeft = "10dp" android:text = "=" android:textSize = "30sp" android:paddingRight = "15sp" android:paddingBottom = "15sp" android:gravity = "center" android:background = "@color/colorAccent" /> </ LinearLayout > </ LinearLayout > |
Activity.java文件实现功能的代码如下:
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package com.example.myapplication; import androidx.appcompat.app.AppCompatActivity; import android.os.Bundle; import android.view.View; import android.widget.Button; import android.widget.EditText; public class Main2Activity extends AppCompatActivity implements View.OnClickListener{ //创建Button对象 也就是activity_main.xml里所设置的ID Button btn_0,btn_1,btn_2,btn_3,btn_4,btn_5,btn_6,btn_7,btn_8,btn_9,btn_pt; Button btn_mul,btn_div,btn_add,btn_sub; Button btn_clr,btn_del,btn_eq; EditText et_input; boolean clr_flag; //判断et编辑文本框中是否清空 @Override protected void onCreate(Bundle savedInstanceState) { super .onCreate(savedInstanceState); setContentView(R.layout.activity_main2); //实例化对象 setContentView(R.layout.activity_main2); btn_0= (Button) findViewById(R.id.btn_0); btn_1= (Button) findViewById(R.id.btn_1); btn_2= (Button) findViewById(R.id.btn_2); btn_3= (Button) findViewById(R.id.btn_3); btn_4= (Button) findViewById(R.id.btn_4); btn_5= (Button) findViewById(R.id.btn_5); btn_6= (Button) findViewById(R.id.btn_6); btn_7= (Button) findViewById(R.id.btn_7); btn_8= (Button) findViewById(R.id.btn_8); btn_9= (Button) findViewById(R.id.btn_9); btn_pt= (Button) findViewById(R.id.btn_pt); btn_add= (Button) findViewById(R.id.btn_add); btn_sub= (Button) findViewById(R.id.btn_sub); btn_mul= (Button) findViewById(R.id.btn_mul); btn_div= (Button) findViewById(R.id.btn_div); btn_clr= (Button) findViewById(R.id.btn_clr); btn_del= (Button) findViewById(R.id.btn_del); btn_eq= (Button) findViewById(R.id.btn_eq); et_input= (EditText) findViewById(R.id.et_input); //给按钮设置的点击事件 btn_0.setOnClickListener( this ); btn_1.setOnClickListener( this ); btn_2.setOnClickListener( this ); btn_3.setOnClickListener( this ); btn_4.setOnClickListener( this ); btn_5.setOnClickListener( this ); btn_6.setOnClickListener( this ); btn_7.setOnClickListener( this ); btn_8.setOnClickListener( this ); btn_9.setOnClickListener( this ); btn_pt.setOnClickListener( this ); btn_add.setOnClickListener( this ); btn_sub.setOnClickListener( this ); btn_mul.setOnClickListener( this ); btn_div.setOnClickListener( this ); btn_clr.setOnClickListener( this ); btn_del.setOnClickListener( this ); btn_eq.setOnClickListener( this ); } @Override public void onClick(View v) { String str=et_input.getText().toString(); switch (v.getId()){ case R.id.btn_0: case R.id.btn_1: case R.id.btn_2: case R.id.btn_3: case R.id.btn_4: case R.id.btn_5: case R.id.btn_6: case R.id.btn_7: case R.id.btn_8: case R.id.btn_9: case R.id.btn_pt: if (clr_flag){ clr_flag= false ; str= "" ; et_input.setText( "" ); } et_input.setText(str+((Button)v).getText()); break ; case R.id.btn_add: case R.id.btn_sub: case R.id.btn_mul: case R.id.btn_div: if (clr_flag){ clr_flag= false ; str= "" ; et_input.setText( "" ); } if (str.contains( "+" )||str.contains( "-" )||str.contains( "×" )||str.contains( "÷" )) { str=str.substring( 0 ,str.indexOf( " " )); } et_input.setText(str+ " " +((Button)v).getText()+ " " ); break ; case R.id.btn_clr: if (clr_flag) clr_flag= false ; str= "" ; et_input.setText( "" ); break ; case R.id.btn_del: //判断是否为空,然后在进行删除 if (clr_flag){ clr_flag= false ; str= "" ; et_input.setText( "" ); } else if (str!= null &&!str.equals( "" )){ et_input.setText(str.substring( 0 ,str.length()- 1 )); } break ; case R.id.btn_eq: //单独运算最后结果 getResult(); //调用下面的方法 break ; } } private void getResult() { String exp=et_input.getText().toString(); if (exp== null ||exp.equals( "" )) return ; //因为没有运算符所以不用运算 if (!exp.contains( " " )){ return ; } if (clr_flag){ clr_flag= false ; return ; } clr_flag= true ; //截取运算符前面的字符串 String s1=exp.substring( 0 ,exp.indexOf( " " )); //截取的运算符 String op=exp.substring(exp.indexOf( " " )+ 1 ,exp.indexOf( " " )+ 2 ); //截取运算符后面的字符串 String s2=exp.substring(exp.indexOf( " " )+ 3 ); double cnt= 0 ; if (!s1.equals( "" )&&!s2.equals( "" )){ double d1=Double.parseDouble(s1); double d2=Double.parseDouble(s2); if (op.equals( "+" )){ cnt=d1+d2; } if (op.equals( "-" )){ cnt=d1-d2; } if (op.equals( "×" )){ cnt=d1*d2; } if (op.equals( "÷" )){ if (d2== 0 ) cnt= 0 ; else cnt=d1/d2; } if (!s1.contains( "." )&&!s2.contains( "." )&&!op.equals( "÷" )) { int res = ( int ) cnt; et_input.setText(res+ "" ); } else { et_input.setText(cnt+ "" );} } //如果s1是空 s2不是空 就执行下一步 else if (!s1.equals( "" )&&s2.equals( "" )){ double d1=Double.parseDouble(s1); if (op.equals( "+" )){ cnt=d1; } if (op.equals( "-" )){ cnt=d1; } if (op.equals( "×" )){ cnt= 0 ; } if (op.equals( "÷" )){ cnt= 0 ; } if (!s1.contains( "." )) { int res = ( int ) cnt; et_input.setText(res+ "" ); } else { et_input.setText(cnt+ "" );} } //如果s1是空 s2不是空 就执行下一步 else if (s1.equals( "" )&&!s2.equals( "" )){ double d2=Double.parseDouble(s2); if (op.equals( "+" )){ cnt=d2; } if (op.equals( "-" )){ cnt= 0 -d2; } if (op.equals( "×" )){ cnt= 0 ; } if (op.equals( "÷" )){ cnt= 0 ; } if (!s2.contains( "." )) { int res = ( int ) cnt; et_input.setText(res+ "" ); } else { et_input.setText(cnt+ "" );} } else { et_input.setText( "" ); } } } |
结果图如下所示:
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:https://blog.csdn.net/wxnshuai/article/details/105456391