Android Studio怎么实现简易计算器App

本篇内容主要讲解"Android Studio怎么实现简易计算器App"，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习"Android Studio怎么实现简易计算器App"吧!

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);    }}

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