鄙人新手 整了 快两天 终于搞定了。。
1.首先是MainActivity 中 在Oncreate函数中 注册
2.按+ 或者 - 号 来分成两大字符串 s1 和 s2
再将s2 分为更小的s1 和 s2 直到 s2不包含+ 或者 -号
思路就是这样，没用递归，递归速度太慢，也不擅长用递归。
3.就是找各种Bug 还有装饰
基本达成目标 和自己手机上安卓的自带计算器基本一样。
改正 双击等于 死机
改正 除数可以为0
改正 不能多个运算符
...未知
项目代码如下：
链接: http://pan.baidu.com/s/1c0dj748 密码: hkyx
写法如下package com.example.administrator.myapplication;
import android.app.Activity;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
public class MainActivity extends Activity implements OnClickListener {
private Button bt_0;
private Button bt_1;
private Button bt_2;
private Button bt_3;
private Button bt_4;
private Button bt_5;
private Button bt_6;
private Button bt_7;
private Button bt_8;
private Button bt_9;
private Button bt_point;
private Button bt_C;
private Button bt_DEL;
private Button bt_minuse;
private Button bt_multipy;
private Button bt_plus;
private Button bt_divide;
private Button bt_dengyu;
private EditText input_text;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
// 注册Button
bt_0 = (Button) findViewById(R.id.bt_0);
bt_1 = (Button) findViewById(R.id.bt_1);
bt_2 = (Button) findViewById(R.id.bt_2);
bt_3 = (Button) findViewById(R.id.bt_3);
bt_4 = (Button) findViewById(R.id.bt_4);
bt_5 = (Button) findViewById(R.id.bt_5);
bt_6 = (Button) findViewById(R.id.bt_6);
bt_7 = (Button) findViewById(R.id.bt_7);
bt_8 = (Button) findViewById(R.id.bt_8);
bt_9 = (Button) findViewById(R.id.bt_9);
bt_point = (Button) findViewById(R.id.bt_point);
bt_C = (Button) findViewById(R.id.bt_clear);
bt_DEL = (Button) findViewById(R.id.bt_del);
bt_minuse = (Button) findViewById(R.id.bt_minuse);
bt_multipy = (Button) findViewById(R.id.bt_multipy);
bt_plus = (Button) findViewById(R.id.bt_plus);
bt_divide = (Button) findViewById(R.id.bt_divide);
bt_dengyu = (Button) findViewById(R.id.bt_dengyu);
input_text = (EditText) findViewById(R.id.edit_text1);
// 监听事件
bt_0.setOnClickListener(this);
bt_1.setOnClickListener(this);
bt_2.setOnClickListener(this);
bt_3.setOnClickListener(this);
bt_4.setOnClickListener(this);
bt_5.setOnClickListener(this);
bt_6.setOnClickListener(this);
bt_7.setOnClickListener(this);
bt_8.setOnClickListener(this);
bt_9.setOnClickListener(this);
bt_point.setOnClickListener(this);
bt_C.setOnClickListener(this);
bt_DEL.setOnClickListener(this);
bt_minuse.setOnClickListener(this);
bt_multipy.setOnClickListener(this);
bt_plus.setOnClickListener(this);
bt_divide.setOnClickListener(this);
bt_dengyu.setOnClickListener(this);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
@Override
public void onClick(View v) {
String str = input_text.getText().toString();
switch (v.getId()) {
case R.id.bt_0:
case R.id.bt_1:
case R.id.bt_2:
case R.id.bt_3:
case R.id.bt_4:
case R.id.bt_5:
case R.id.bt_6:
case R.id.bt_7:
case R.id.bt_8:
case R.id.bt_9:
input_text.setText(str + ((Button) v).getText());
break;
case R.id.bt_point:
if (!str.contains(".")) input_text.setText(str + ((Button) v).getText());
break;
case R.id.bt_plus:
case R.id.bt_minuse:
case R.id.bt_multipy:
case R.id.bt_divide:
if(str.equals(""));
else {
char a =str.charAt(str.length()-1);
Log.i("str",str+"");
Log.i("最后一位字符",a+"");
if( a ==' ' );
else {
input_text.setText(str + " " + ((Button) v).getText() + " ");
}
a =str.charAt(str.length()-1);
break;
}
break;
case R.id.bt_clear:
input_text.setText(null);
break;
case R.id.bt_del:
if (str != null && !str.equals("")) {
input_text.setText(str.substring(0, str.length() - 1));
}
break;
case R.id.bt_dengyu:
getRseult();
break;
}
}
//运算结果
private void getRseult() {
String str = input_text.getText().toString();
if (str == null || str.equals(""))
return;
if(!str.contains("+") &&!str.contains("-")&&!str.contains("×")&&!str.contains("÷") )
return;
//遍历计算result
double result = 0;
char a =str.charAt(str.length()-2);
if(a == '+' || a == '-'){
str = str + '0';
}
else if(a == '×' || a == '÷'){
str = str + '1';
}
int i = 0;
int start = 0;
char temp =' ';
int flag = 1;
if(!str.contains("+") &&!str.contains("-")){
result += calculate_include_multy_or_minuse(str);
}
else {
for (; i < str.length(); i++) {
char c = str.charAt(i);
if (c == '+' || c == '-') {
String s1 = str.substring(start, i);
Log.i("S1是", s1 + "");
if(flag == 0) result -= calculate_include_multy_or_minuse(s1);
else result += calculate_include_multy_or_minuse(s1);
start = i + 1;
if(c == '-') flag = 0;
else flag = 1;
String s2 = str.substring(start, str.length());
Log.i("S2是", s2 + "");
if (s2.contains("+") || s2.contains("-")) {
temp = c;
continue;
}
else {
if(flag == 0) {
result -= calculate_include_multy_or_minuse(s2);
}
else result += calculate_include_multy_or_minuse(s2);
}
}
}
}
int r = 0;
String result_string = Double.toString(result);
if(Double.toString(result) == "Infinity") input_text.setText("傻啊？除数为0");
else if ((int)result == result){
r = (int)result;
input_text.setText(r + "");
}
else
input_text.setText(result + "");
}
private double calculate(String s) {
double sum = 1;
int start = 0;
int flag = 0;
int flag2 = 0;
s = s + '×';
char op = ' ';
for (int i = 0; i < s.length(); i++) {
char c = s.charAt(i);
if (c == '×' || c == '÷') {
if (flag2 == 0) op = c;
String s1 = s.substring(start, i);
if (flag == 0) {
sum *= Double.parseDouble(s1);
// Log.i("第一个是"," "+sum);
flag = 1;
flag2 = 1;
} else {
switch (op) {
case '×':
// Log.i("s1是"," "+s1);
sum = sum * Double.parseDouble(s1);
// Log.i("sum是"," "+sum);
break;
case '÷':
// Log.i("s2是"," "+s1);
sum = sum / Double.parseDouble(s1);
// Log.i("sum是"," "+sum);
break;
}
}
op = c;
start = i + 1;
}
}
// Log.i("sum的结果是", " " + sum);
return sum;
}
private double calculate_include_multy_or_minuse(String s) {
double sum = 0;
if (s.contains("×") || s.contains("÷")) {
sum = calculate(s);
} else {
sum = Double.parseDouble(s);
}
return sum;
}
}