Android studio四则运算计算器(加、减、乘、除)

package com.example.wangliyong.calculator;import android.support.v7.app.AppCompatActivity;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.TextView;import android.widget.Toast;public class MainActivity extends AppCompatActivity implements View.OnClickListener { Button bt_0, bt_1, bt_2, bt_3, bt_4, bt_5, bt_6, bt_7, bt_8, bt_9, bt_multiply, bt_divide, bt_add, bt_minus, bt_point, bt_del, bt_equal,bt_left,bt_right, bt_clean,bt_ci,bt_sin,bt_cos,bt_tan,bt_lg,bt_gen; TextView text_input ; //显示输入的表达式或运算结果 boolean clear_flag=false; int point_flag=0; private static final String TEXTVIEW_DATA = "data"; //对应旋转过程中保存text_input中的表达式的extra @Override public void onSaveInstanceState(Bundle sacedInstance){ //保存text_input的表达式 super.onSaveInstanceState(sacedInstance); sacedInstance.putString(TEXTVIEW_DATA,text_input.getText().toString()); } @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); if(getSupportActionBar() != null ){ //隐藏标题栏 getSupportActionBar().hide(); } setContentView(R.layout.calculator_act); 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_multiply = (Button) findViewById(R.id.bt_multiply); bt_divide = (Button) findViewById(R.id.bt_divide); bt_add = (Button) findViewById(R.id.bt_add); bt_minus = (Button) findViewById(R.id.bt_minus); bt_point = (Button) findViewById(R.id.bt_point); bt_del = (Button) findViewById(R.id.bt_del); bt_equal = (Button) findViewById(R.id.bt_equal); bt_clean = (Button) findViewById(R.id.bt_clean); bt_right = (Button)findViewById(R.id.bt_right); bt_left = (Button)findViewById(R.id.bt_left); bt_ci = (Button)findViewById(R.id.bt_ci); bt_lg = (Button)findViewById(R.id.bt_lg); bt_sin = (Button)findViewById(R.id.bt_sin); bt_cos = (Button)findViewById(R.id.bt_cos); bt_tan =(Button)findViewById(R.id.bt_tan); bt_gen = (Button)findViewById(R.id.bt_gen); text_input = (TextView) findViewById(R.id.textView); if(savedInstanceState != null ){ text_input.setText(savedInstanceState.getString(TEXTVIEW_DATA)); } 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_minus.setOnClickListener(this); bt_multiply.setOnClickListener(this); bt_del.setOnClickListener(this); bt_divide.setOnClickListener(this); bt_point.setOnClickListener(this); bt_add.setOnClickListener(this); bt_equal.setOnClickListener(this); bt_clean.setOnClickListener(this); bt_left.setOnClickListener(this); bt_right.setOnClickListener(this); bt_sin.setOnClickListener(this); bt_cos.setOnClickListener(this); bt_tan.setOnClickListener(this); bt_lg.setOnClickListener(this); bt_ci.setOnClickListener(this); bt_gen.setOnClickListener(this); } @Override public void onClick(View v) { String str = text_input.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: if (clear_flag) { //如果清零标志为true则删除 clear_flag = false; str=""; text_input.setText(""); } text_input.setText(str ((Button) v).getText() ); //获得输入的数字 break; case R.id.bt_left: case R.id.bt_right: case R.id.bt_gen: case R.id.bt_ci: case R.id.bt_lg: case R.id.bt_sin: case R.id.bt_cos: case R.id.bt_tan: case R.id.bt_add: case R.id.bt_minus: case R.id.bt_multiply: case R.id.bt_divide: try{ point_flag = point_flag 1; if (clear_flag) { //如果清零标志为true则删除 clear_flag = false; text_input.setText(str ((Button)v).getText()); } if (str != null && ((((Button) v).getText().equals("×"))||(((Button) v).getText().equals("-"))|| (((Button) v).getText().equals(" "))|| (((Button) v).getText().equals("÷")))&& ("÷".equals(Character.toString(str.charAt(str.length()-1))) || "×".equals(Character.toString(str.charAt(str.length()-1))) || " ".equals(Character.toString(str.charAt(str.length()-1))) || "-".equals(Character.toString(str.charAt(str.length()-1))))){ break; } text_input.setText(str ((Button) v).getText() ); //获得输入的运算符 break; }catch (Exception e){ str=""; text_input.setText(""); break; } case R.id.bt_del: if (clear_flag) { //如果清零标志为true则删除 clear_flag = false; str = ""; text_input.setText(""); } else if (str != null && !str.equals("")) { if(".".equals(Character.toString(str.charAt(str.length()-1)))){ point_flag = point_flag 1; } text_input.setText(str.substring(0, str.length() - 1)); //删除最后一个字符 } break; case R.id.bt_clean: //清空text_input point_flag = 0; clear_flag = false; str = ""; text_input.setText(""); break; case R.id.bt_equal: point_flag = 0; clear_flag = true; if("".equals(str)) { str = ""; text_input.setText(""); }else{ getResult(); //计算结果 } break; case R.id.bt_point: if(point_flag>=0){ point_flag = point_flag-1; if (clear_flag) { //如果清零标志为true则删除 clear_flag = false; str=""; text_input.setText(""); } text_input.setText(str ((Button) v).getText() ); //获得输入的数字 break; } } } //运算结果 private void getResult() { clear_flag = true; String s = text_input.getText().toString(); PostfixExpression temp = new PostfixExpression(s); try{ String str = Double.toString(temp.calculate()); //计算text_input中字符串的结果 //正则表达式 if(str.indexOf(".")>0) { //去掉多余的0 str = str.replaceAll("0 ?$",""); //去掉整数后面的小数点及0 str = str.replaceAll("[.]$",""); } text_input.setText(str); }catch (Exception e){ text_input.setText("错误"); } }}