Android 计算器制作 2.注册View 构建函数

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;
    }
}