本文实例为大家分享了android studio实现简易计算器app的具体代码，供大家参考，具体内容如下
效果演示
布局文件
java文件
import android.app.activity;
import android.os.bundle;
import android.view.view;
import android.widget.textview;
import android.widget.toast;
import androidx.annotation.nullable;
public class mainactivity extends activity {
private textview tv1;
private textview tv2;
private stringbuilder viewstr;
private int index = 0;
@override
protected void oncreate(@nullable bundle savedinstancestate) {
super.oncreate(savedinstancestate);
setcontentview(r.layout.main_calc);
tv1 = (textview) findviewbyid(r.id.mini);
tv2 = (textview) findviewbyid(r.id.max);
viewstr = new stringbuilder();
index = 0;
}
//加减乘除、求余简单运算方法
public string calc(stringbuilder strb) {
string alls = strb.tostring();
string[] asmd = {"＋","－","×","÷","%"};
int x = 0; int y = 0;
string result = null;
for (int i = 0; i < 5; i ) {
int inde = strb.indexof(asmd[i]);
if (inde > 0) {
string a = alls.split(asmd[i])[0];
string b = alls.split(asmd[i])[1];
if (i == 0) {result = string.valueof(integer.parseint(a) integer.parseint(b));}
if (i == 1) {result = string.valueof(integer.parseint(a) - integer.parseint(b));}
if (i == 2) {result = string.valueof(integer.parseint(a) * integer.parseint(b));}
if (i == 3) {
if (integer.parseint(b) == 0) {
toast.maketext(this,"0不能为除数",toast.length_short).show();
result = string.valueof(integer.parseint(a));
}else {
result = string.valueof(integer.parseint(a) / integer.parseint(b));
}
}
if (i == 4) {result = string.valueof(integer.parseint(a) % integer.parseint(b));}
}
}
return result;
}
//数字按钮事件
public void number_0(view view) { viewstr.append("0"); index ; tv2.settext(viewstr); }
public void number_1(view view) { viewstr.append("1"); index ; tv2.settext(viewstr); }
public void number_2(view view) { viewstr.append("2"); index ; tv2.settext(viewstr); }
public void number_3(view view) { viewstr.append("3"); index ; tv2.settext(viewstr); }
public void number_4(view view) { viewstr.append("4"); index ; tv2.settext(viewstr); }
public void number_5(view view) { viewstr.append("5"); index ; tv2.settext(viewstr); }
public void number_6(view view) { viewstr.append("6"); index ; tv2.settext(viewstr); }
public void number_7(view view) { viewstr.append("7"); index ; tv2.settext(viewstr); }
public void number_8(view view) { viewstr.append("8"); index ; tv2.settext(viewstr); }
public void number_9(view view) { viewstr.append("9"); index ; tv2.settext(viewstr); }
//回退按钮事件
public void backsprce(view view) {
if (viewstr.length() == 0) return;
index = viewstr.length();
viewstr.deletecharat(--index); tv2.settext(viewstr);
}
//符号改变按钮事件
public void change(view view) {
string alls = viewstr.tostring();
string[] asmd = {"＋","－","×","÷","%"};
int inde = 0;
string a = null; //保存字符串中运算符部分
string b = null; //保存字符串中数字部分
for (int i = 0; i < 5; i ) {
inde = viewstr.indexof(asmd[i]);
if (inde != -1) {
a = asmd[i];
break;
}
}
//a 字符形 改变 a 正负值
if (inde == -1) {
clearc(view);
int c = - integer.parseint(alls);
viewstr.append(string.valueof(c));
index = string.valueof(c).length();
tv2.settext(viewstr);
}
//a 字符串形 改变 a 正负值 暂时无法实现，待后续优化
if (inde == index - 1) {
return;
// clearc(view);
// int c = - integer.valueof(alls.split(a)[0]);
// viewstr.append(string.valueof(c));
// index = string.valueof(c).length();
// tv2.settext(viewstr);
}
//a b 字符串形 改变 b 正负值
if (inde >= 0 && inde < index) {
clearc(view);
b = alls.split(a)[0];
int c = - integer.parseint(alls.split(a)[1]);
viewstr.append(b).append(a).append(string.valueof(c));
index = string.valueof(c).length();
tv2.settext(viewstr);
}
}
//清空按钮事件
public void clearc(view view) {
stringbuilder temp = new stringbuilder();
viewstr = temp.append("");
tv2.settext(viewstr);
index = 0;
}
public void clearce(view view) {
stringbuilder temp = new stringbuilder();
viewstr = temp.append("");
tv1.settext("");
tv2.settext(viewstr);
index = 0;
}
//等于按钮事件
public void equal(view view) {
string[] asmd = {"＋","－","×","÷","%"};
stringbuilder temp = new stringbuilder();
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > 0 && inde != index-1) {
tv1.settext(calc(viewstr));
string a = calc(viewstr);
viewstr = temp.append(a);
tv2.settext(viewstr);
index = viewstr.length();
return;
}else if (inde > 0 && inde == index-1) {
viewstr.deletecharat(--index);
tv1.settext(viewstr);
tv2.settext(viewstr);
}
}
tv1.settext(viewstr);
tv2.settext(viewstr);
}
//加减乘除按钮事件
public void addition(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
stringbuilder temp = new stringbuilder();
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > 0 && viewstr.charat(index-1) >= '0' && viewstr.charat(index-1) <= '9') {
tv1.settext(calc(viewstr));
string a = calc(viewstr);
viewstr = temp.append(a).append('＋');
tv2.settext(viewstr);
index = viewstr.length();
return;
}
}
char a = viewstr.charat(index-1);
if (a == '＋') { return; }
if (a == '－' || a == '×' || a == '÷' || a == '%') {
viewstr.setcharat(index-1,'＋');
}else {
viewstr.append("＋");
index ;
}
tv2.settext(viewstr);
}
public void subtraction(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
stringbuilder temp = new stringbuilder();
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > 0 && viewstr.charat(index-1) >= '0' && viewstr.charat(index-1) <= '9') {
tv1.settext(calc(viewstr));
string a = calc(viewstr);
viewstr = temp.append(a).append('－');
tv2.settext(viewstr);
index = viewstr.length();
return;
}
}
char a = viewstr.charat(index-1);
if (a == '－') { return; }
if (a == '＋' || a == '×' || a == '÷' || a == '%') {
viewstr.setcharat(index-1,'－');
}else {
viewstr.append("－");
index ;
}
tv2.settext(viewstr);
}
public void multiplication(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
stringbuilder temp = new stringbuilder();
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > 0 && viewstr.charat(index-1) >= '0' && viewstr.charat(index-1) <= '9') {
tv1.settext(calc(viewstr));
string a = calc(viewstr);
viewstr = temp.append(a).append('×');
tv2.settext(viewstr);
index = viewstr.length();
return;
}
}
char a = viewstr.charat(index-1);
if (a == '×') { return; }
if (a == '＋' || a == '－' || a == '÷' || a == '%') {
viewstr.setcharat(index-1,'×');
}else {
viewstr.append("×");
index ;
}
tv2.settext(viewstr);
}
public void division(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
stringbuilder temp = new stringbuilder();
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > 0 && viewstr.charat(index-1) >= '0' && viewstr.charat(index-1) <= '9') {
tv1.settext(calc(viewstr));
string a = calc(viewstr);
viewstr = temp.append(a).append('÷');
tv2.settext(viewstr);
index = viewstr.length();
return;
}
}
char a = viewstr.charat(index-1);
if (a == '÷') { return; }
if (a == '＋' || a == '－' || a == '×' || a == '%') {
viewstr.setcharat(index-1,'÷');
}else {
viewstr.append("÷");
index ;
}
tv2.settext(viewstr);
}
//求余按钮事件
public void surplus(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
stringbuilder temp = new stringbuilder();
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > 0 && viewstr.charat(index-1) >= '0' && viewstr.charat(index-1) <= '9') {
tv1.settext(calc(viewstr));
string a = calc(viewstr);
viewstr = temp.append(a).append('%');
tv2.settext(viewstr);
index = viewstr.length();
return;
}
}
char a = viewstr.charat(index-1);
if (a == '%') { return; }
if (a == '＋' || a == '－' || a == '×' || a == '÷') {
viewstr.setcharat(index-1,'%');
}else {
viewstr.append("%");
index ;
}
tv2.settext(viewstr);
}
//求倒数按钮事件
public void reciprocal(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > -1) { return; }
}
int a = integer.parseint(viewstr.tostring().trim());
if (a == 0) {
toast.maketext(this,"0不能为除数",toast.length_short).show();
return;
}
clearc(view);
viewstr.append(1/a);
index = string.valueof(1/a).length();
tv2.settext(viewstr);
}
//平方按钮事件
public void square(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > -1) { return; }
}
int a = integer.parseint(viewstr.tostring().trim());
clearc(view);
viewstr.append(a*a);
index = string.valueof(a*a).length();
tv2.settext(viewstr);
}
//开平方按钮事件
public void squareroot(view view) {
if (viewstr.length() == 0) return;
string[] asmd = {"＋","－","×","÷","%"};
for (int i = 0; i < 5; i ) {
int inde = viewstr.indexof(asmd[i]);
if (inde > -1) { return; }
}
int a = integer.parseint(viewstr.tostring().trim());
clearc(view);
viewstr.append((int)math.sqrt(a));
index = string.valueof((int)math.sqrt(a)).length();
tv2.settext(viewstr);
}
}
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。
