上个星期的时候，我想教我朋友做一个简单的app。想来想去教什么比較好。当时看见小米的计算器认为比較美丽，就想这个简单。然后就開始动手做了。我以为能够一个小时能够搞定。没想到花了快一天的时间。
哎。突然想起曾经公司的CTO的话，一切都是从简单開始的。
我自己的思路是：将计算器的item分为：integer，float，运算符，用list去存储。
然后我通过标记上一次输入的标记。推断它是否该插入list还是拿到last改动。然后依据先遍历高级运算，得到结果，将i-1设置为得到的结果。移除i+1,i。
再遍历低级运算，最后得到list(0)就是所须要的结果。当然，肯定须要非常多推断之类，由于demo的原因，我没有再去改善它。由于这个毕竟是我个人思路，假设有哪位朋友有更好的想法，能够给我留言。
1.输入的model
package com.example.calculator;
public class InputItem {
private String input;
private int type;
public InputItem() {
super();
}
public InputItem(String input, int type) {
super();
this.input = input;
this.type = type;
}
public String getInput() {
return input;
}
public void setInput(String input) {
this.input = input;
}
public int getType() {
return type;
}
public void setType(int type) {
this.type = type;
}
interface InputType {
public static final int INT_TYPE = 0; //int 类型
public static final int DOUBLE_TYPE=1; //double 类型
public static final int OPERATOR_TYPE = 2; //操作符类型
public static final int ERROR = 3; //操作符类型
}
@Override
public String toString() {
return "InputItem [input=" + input + ", type=" + type + "]";
}
}
2.逻辑运算
package com.example.calculator;
import java.math.BigDecimal;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import com.example.calculator.InputItem.InputType;
import android.os.Bundle;
import android.os.Handler;
import android.os.Message;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.animation.Animation;
import android.view.animation.AnimationUtils;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity implements OnClickListener{
private TextView mShowResultTv; //显示结果
private TextView mShowInputTv; //显示输入的字符
private Button mCBtn;
private Button mDelBtn;
private Button mAddBtn;
private Button mSubBtn;
private Button mMultiplyBtn;
private Button mDividebtn;
private Button mZeroButton;
private Button mOnebtn;
private Button mTwoBtn;
private Button mThreeBtn;
private Button mFourBtn;
private Button mFiveBtn;
private Button mSixBtn;
private Button mSevenBtn;
private Button mEightBtn;
private Button mNineBtn;
private Button mPointtn;
private Button mEqualBtn;
private HashMap<View,String> map; //将View和String映射起来
private List<InputItem> mInputList; //定义记录每次输入的数
private int mLastInputstatus = INPUT_NUMBER; //记录上一次输入状态
public static final int INPUT_NUMBER = 1;
public static final int INPUT_POINT = 0;
public static final int INPUT_OPERATOR = -1;
public static final int END = -2;
public static final int ERROR= -3;
public static final int SHOW_RESULT_DATA = 1;
public static final String nan = "NaN";
public static final String infinite = "∞";
@SuppressLint("HandlerLeak")
private Handler mHandler = new Handler(){
public void handleMessage(Message msg) {
if(msg.what == SHOW_RESULT_DATA){
mShowResultTv.setText(mShowInputTv.getText());
mShowInputTv.setText(mInputList.get(0).getInput());
clearScreen(mInputList.get(0));
}
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
initView();
initData();
}
/**
* 初始化view
*/
private void initView() {
mShowResultTv = (TextView) this.findViewById(R.id.show_result_tv);
mShowInputTv = (TextView)this.findViewById(R.id.show_input_tv);
mCBtn = (Button)this.findViewById(R.id.c_btn);
mDelBtn= (Button)this.findViewById(R.id.del_btn);
mAddBtn= (Button)this.findViewById(R.id.add_btn);
mMultiplyBtn= (Button)this.findViewById(R.id.multiply_btn);
mDividebtn= (Button)this.findViewById(R.id.divide_btn);
mZeroButton = (Button)this.findViewById(R.id.zero_btn);
mOnebtn= (Button)this.findViewById(R.id.one_btn);
mTwoBtn= (Button)this.findViewById(R.id.two_btn);
mThreeBtn= (Button)this.findViewById(R.id.three_btn);
mFourBtn= (Button)this.findViewById(R.id.four_btn);
mFiveBtn= (Button)this.findViewById(R.id.five_btn);
mSixBtn= (Button)this.findViewById(R.id.six_btn);
mSevenBtn= (Button)this.findViewById(R.id.seven_btn);
mEightBtn= (Button)this.findViewById(R.id.eight_btn);
mNineBtn= (Button)this.findViewById(R.id.nine_btn);
mPointtn= (Button)this.findViewById(R.id.point_btn);
mEqualBtn= (Button)this.findViewById(R.id.equal_btn);
mSubBtn = (Button)this.findViewById(R.id.sub_btn);
setOnClickListener();//调用监听事件
}
/**
* 初始化数据
*/
private void initData() {
if(map == null)
map = new HashMap<View, String>();
map.put(mAddBtn,getResources().getString(R.string.add));
map.put(mMultiplyBtn,getResources().getString(R.string.multply));
map.put(mDividebtn,getResources().getString(R.string.divide));
map.put(mSubBtn, getResources().getString(R.string.sub));
map.put(mZeroButton ,getResources().getString(R.string.zero));
map.put(mOnebtn,getResources().getString(R.string.one));
map.put(mTwoBtn,getResources().getString(R.string.two));
map.put(mThreeBtn,getResources().getString(R.string.three));
map.put(mFourBtn,getResources().getString(R.string.four));
map.put(mFiveBtn,getResources().getString(R.string.five));
map.put(mSixBtn,getResources().getString(R.string.six));
map.put(mSevenBtn,getResources().getString(R.string.seven));
map.put(mEightBtn,getResources().getString(R.string.eight));
map.put(mNineBtn,getResources().getString(R.string.nine));
map.put(mPointtn,getResources().getString(R.string.point));
map.put(mEqualBtn,getResources().getString(R.string.equal));
mInputList = new ArrayList<InputItem>();
mShowResultTv.setText("");
clearAllScreen();
}
/**
* 设置监听事件
*/
private void setOnClickListener() {
mCBtn.setOnClickListener(this);
mDelBtn.setOnClickListener(this);
mAddBtn.setOnClickListener(this);
mMultiplyBtn.setOnClickListener(this);
mDividebtn.setOnClickListener(this);
mSubBtn.setOnClickListener(this);
mZeroButton.setOnClickListener(this);
mOnebtn.setOnClickListener(this);
mTwoBtn.setOnClickListener(this);
mThreeBtn.setOnClickListener(this);
mFourBtn.setOnClickListener(this);
mFiveBtn.setOnClickListener(this);
mSixBtn.setOnClickListener(this);
mSevenBtn.setOnClickListener(this);
mEightBtn.setOnClickListener(this);
mNineBtn.setOnClickListener(this);
mPointtn.setOnClickListener(this);
mEqualBtn.setOnClickListener(this);
}
/**
* 点击事件
*/
@Override
public void onClick(View arg0) {
switch (arg0.getId()) {
case R.id.c_btn:
clearAllScreen();
break;
case R.id.del_btn:
back();
break;
case R.id.point_btn:
inputPoint(arg0);
break;
case R.id.equal_btn:
operator();
break;
case R.id.add_btn:
case R.id.sub_btn:
case R.id.multiply_btn:
case R.id.divide_btn:
inputOperator(arg0);
break;
default:
inputNumber(arg0);
break;
}
}
/**
* 点击=之后開始运算
*/
private void operator() {
if(mLastInputstatus == END ||mLastInputstatus == ERROR || mLastInputstatus == INPUT_OPERATOR|| mInputList.size()==1){
return;
}
mShowResultTv.setText("");
startAnim();
findHighOperator(0);
if(mLastInputstatus != ERROR){
findLowOperator(0);
}
mHandler.sendMessageDelayed(mHandler.obtainMessage(SHOW_RESULT_DATA), 300);
}
private void startAnim(){
mShowInputTv.setText(mShowInputTv.getText()+getResources().getString(R.string.equal));
Animation anim = AnimationUtils.loadAnimation(this, R.anim.screen_anim);
mShowInputTv.startAnimation(anim);
}
/**
* 输入点
* @param view
*/
private void inputPoint(View view) {
if(mLastInputstatus == INPUT_POINT){
return;
}
if(mLastInputstatus == END || mLastInputstatus == ERROR){
clearInputScreen();
}
String key = map.get(view);
String input = mShowInputTv.getText().toString();
if(mLastInputstatus == INPUT_OPERATOR){
input = input+"0";
}
mShowInputTv.setText(input+key);
addInputList(INPUT_POINT, key);
}
/**
* 输入数字
* @param view
*/
private void inputNumber(View view){
if(mLastInputstatus == END || mLastInputstatus == ERROR){
clearInputScreen();
}
String key = map.get(view);
if("0".equals(mShowInputTv.getText().toString())){
mShowInputTv.setText(key);
}else{
mShowInputTv.setText(mShowInputTv.getText() + key);
}
addInputList(INPUT_NUMBER, key);
}
/**
* 输入运算符
* @param view
*/
private void inputOperator(View view) {
if(mLastInputstatus == INPUT_OPERATOR || mLastInputstatus == ERROR){
return;
}
if(mLastInputstatus == END){
mLastInputstatus = INPUT_NUMBER;
}
String key = map.get(view);
if("0".equals(mShowInputTv.getText().toString())){
mShowInputTv.setText("0"+key);
mInputList.set(0,new InputItem("0",InputItem.InputType.INT_TYPE));
}else{
mShowInputTv.setText(mShowInputTv.getText() + key);
}
addInputList(INPUT_OPERATOR, key);
}
/**
* 回退操作
*/
private void back() {
if(mLastInputstatus == ERROR){
clearInputScreen();
}
String str = mShowInputTv.getText().toString();
if(str.length() != 1){
mShowInputTv.setText(str.substring(0, str.length()-1));
backList();
}else{
mShowInputTv.setText(getResources().getString(R.string.zero));
clearScreen(new InputItem("",InputItem.InputType.INT_TYPE));
}
}
/**
* 回退InputList操作
*/
private void backList() {
InputItem item = mInputList.get(mInputList.size() - 1);
if (item.getType() == InputItem.InputType.INT_TYPE) {
//获取到最后一个item,并去掉最后一个字符
String input = item.getInput().substring(0,
item.getInput().length() - 1);
//假设截完了，则移除这个item，并将当前状态改为运算操作符
if ("".equals(input)) {
mInputList.remove(item);
mLastInputstatus = INPUT_OPERATOR;
} else {
//否则设置item为截取完的字符串。并将当前状态改为number
item.setInput(input);
mLastInputstatus = INPUT_NUMBER;
}
//假设item是运算操作符 则移除。
} else if (item.getType() == InputItem.InputType.OPERATOR_TYPE) {
mInputList.remove(item);
if (mInputList.get(mInputList.size() - 1).getType() == InputItem.InputType.INT_TYPE) {
mLastInputstatus = INPUT_NUMBER;
} else {
mLastInputstatus = INPUT_POINT;
}
//假设当前item是小数
} else {
String input = item.getInput().substring(0,
item.getInput().length() - 1);
if ("".equals(input)) {
mInputList.remove(item);
mLastInputstatus = INPUT_OPERATOR;
} else {
if (input.contains(".")) {
item.setInput(input);
mLastInputstatus = INPUT_POINT;
} else {
item.setInput(input);
mLastInputstatus = INPUT_NUMBER;
}
}
}
}
//清理屏
private void clearAllScreen() {
clearResultScreen();
clearInputScreen();
}
private void clearResultScreen(){
mShowResultTv.setText("");
}
private void clearInputScreen() {
mShowInputTv.setText(getResources().getString(R.string.zero));
mLastInputstatus = INPUT_NUMBER;
mInputList.clear();
mInputList.add(new InputItem("", InputItem.InputType.INT_TYPE));
}
//计算完毕
private void clearScreen(InputItem item) {
if(mLastInputstatus != ERROR){
mLastInputstatus = END;
}
mInputList.clear();
mInputList.add(item);
}
//实现高级运算
public int findHighOperator(int index) {
if (mInputList.size() > 1 && index >= 0 && index < mInputList.size())
for (int i = index; i < mInputList.size(); i++) {
InputItem item = mInputList.get(i);
if (getResources().getString(R.string.divide).equals(item.getInput())
|| getResources().getString(R.string.multply).equals(item.getInput())) {
int a,b; double c,d;
if(mInputList.get(i - 1).getType() == InputItem.InputType.INT_TYPE){
a = Integer.parseInt(mInputList.get(i - 1).getInput());
if(mInputList.get(i + 1).getType() == InputItem.InputType.INT_TYPE){
b = Integer.parseInt(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.multply).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(a * b),InputItem.InputType.INT_TYPE));
}else{
if(b == 0){
mLastInputstatus = ERROR;
if(a==0){
clearScreen(new InputItem(nan,InputType.ERROR));
}else{
clearScreen(new InputItem(infinite,InputType.ERROR));
}
return -1;
}else if(a % b != 0){
mInputList.set(i - 1,new InputItem(String.valueOf((double)a / b),InputItem.InputType.DOUBLE_TYPE));
}else{
mInputList.set(i - 1,new InputItem(String.valueOf((Integer)a / b),InputItem.InputType.INT_TYPE));
}
}
}else{
d = Double.parseDouble(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.multply).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(a * d),InputItem.InputType.DOUBLE_TYPE));
}else{
if(d == 0){
mLastInputstatus = ERROR;
if(a==0){
clearScreen(new InputItem(nan,InputType.ERROR));
}else{
clearScreen(new InputItem(infinite,InputType.ERROR));
}
return -1;
}
mInputList.set(i - 1,new InputItem(String.valueOf(a / d),InputItem.InputType.DOUBLE_TYPE));
}
}
}else{
c = Double.parseDouble(mInputList.get(i-1).getInput());
if(mInputList.get(i + 1).getType() == InputItem.InputType.INT_TYPE){
b = Integer.parseInt(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.multply).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(c* b),InputItem.InputType.DOUBLE_TYPE));
}else{
if(b== 0){
mLastInputstatus = ERROR;
if(c==0){
clearScreen(new InputItem(nan,InputType.ERROR));
}else{
clearScreen(new InputItem(infinite,InputType.ERROR));
}
return -1;
}
mInputList.set(i - 1,new InputItem(String.valueOf(c / b),InputItem.InputType.DOUBLE_TYPE));
}
}else{
d = Double.parseDouble(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.multply).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(mul(c,d)),InputItem.InputType.DOUBLE_TYPE));
}else{
if(d == 0){
mLastInputstatus = ERROR;
if(c==0){
clearScreen(new InputItem(nan,InputType.ERROR));
}else{
clearScreen(new InputItem(infinite,InputType.ERROR));
}
return -1;
}
mInputList.set(i - 1,new InputItem(String.valueOf(div(c, d)),InputItem.InputType.DOUBLE_TYPE));
}
}
}
mInputList.remove(i + 1);
mInputList.remove(i);
return findHighOperator(i);
}
}
return -1;
}
public int findLowOperator(int index) {
if (mInputList.size()>1 && index >= 0 && index < mInputList.size())
for (int i = index; i < mInputList.size(); i++) {
InputItem item = mInputList.get(i);
if (getResources().getString(R.string.sub).equals(item.getInput())
|| getResources().getString(R.string.add).equals(item.getInput())) {
int a,b; double c,d;
if(mInputList.get(i - 1).getType() == InputItem.InputType.INT_TYPE){
a = Integer.parseInt(mInputList.get(i - 1).getInput());
if(mInputList.get(i + 1).getType() == InputItem.InputType.INT_TYPE){
b = Integer.parseInt(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.add).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(a + b),InputItem.InputType.INT_TYPE));
}else{
mInputList.set(i - 1,new InputItem(String.valueOf(a - b),InputItem.InputType.INT_TYPE));
}
}else{
d = Double.parseDouble(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.add).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(a + d),InputItem.InputType.DOUBLE_TYPE));
}else{
mInputList.set(i - 1,new InputItem(String.valueOf(a - d),InputItem.InputType.DOUBLE_TYPE));
}
}
}else{
c = Double.parseDouble(mInputList.get(i-1).getInput());
if(mInputList.get(i + 1).getType() == InputItem.InputType.INT_TYPE){
b = Integer.parseInt(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.add).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(c + b),InputItem.InputType.DOUBLE_TYPE));
}else{
mInputList.set(i - 1,new InputItem(String.valueOf(c - b),InputItem.InputType.DOUBLE_TYPE));
}
}else{
d = Double.parseDouble(mInputList.get(i + 1).getInput());
if(getResources().getString(R.string.add).equals(item.getInput())){
mInputList.set(i - 1,new InputItem( String.valueOf(add(c, d)),InputItem.InputType.DOUBLE_TYPE));
}else{
mInputList.set(i - 1,new InputItem(String.valueOf(sub(c,d)),InputItem.InputType.DOUBLE_TYPE));
}
}
}
mInputList.remove(i + 1);
mInputList.remove(i);
return findLowOperator(i);
}
}
return -1;
}
//currentStatus 当前状态 9 "9" "+"
void addInputList(int currentStatus,String inputChar){
switch (currentStatus) {
case INPUT_NUMBER:
if(mLastInputstatus == INPUT_NUMBER){
InputItem item = (InputItem)mInputList.get(mInputList.size()-1);
item.setInput(item.getInput()+inputChar);
item.setType(InputItem.InputType.INT_TYPE);
mLastInputstatus = INPUT_NUMBER;
}else if(mLastInputstatus == INPUT_OPERATOR){
InputItem item = new InputItem(inputChar, InputItem.InputType.INT_TYPE);
mInputList.add(item);
mLastInputstatus = INPUT_NUMBER;
}else if(mLastInputstatus == INPUT_POINT){
InputItem item = (InputItem)mInputList.get(mInputList.size()-1);
item.setInput(item.getInput()+inputChar);
item.setType(InputItem.InputType.DOUBLE_TYPE);
mLastInputstatus = INPUT_POINT;
}
break;
case INPUT_OPERATOR:
InputItem item = new InputItem(inputChar, InputItem.InputType.OPERATOR_TYPE);
mInputList.add(item);
mLastInputstatus = INPUT_OPERATOR;
break;
case INPUT_POINT://point
if(mLastInputstatus == INPUT_OPERATOR){
InputItem item1 = new InputItem("0"+inputChar,InputItem.InputType.DOUBLE_TYPE);
mInputList.add(item1);
mLastInputstatus = INPUT_POINT;
}else{
InputItem item1 = (InputItem)mInputList.get(mInputList.size()-1);
item1.setInput(item1.getInput()+inputChar);
item1.setType(InputItem.InputType.DOUBLE_TYPE);
mLastInputstatus = INPUT_POINT;
}
break;
}
}
public static Double div(Double v1,Double v2){
BigDecimal b1 = new BigDecimal(v1.toString());
BigDecimal b2 = new BigDecimal(v2.toString());
return b1.divide(b2,10,BigDecimal.ROUND_HALF_UP).doubleValue();
}
public static Double sub(Double v1,Double v2){
BigDecimal b1 = new BigDecimal(v1.toString());
BigDecimal b2 = new BigDecimal(v2.toString());
return b1.subtract(b2).doubleValue();
}
public static Double add(Double v1,Double v2){
BigDecimal b1 = new BigDecimal(v1.toString());
BigDecimal b2 = new BigDecimal(v2.toString());
return b1.add(b2).doubleValue();
}
public static Double mul(Double v1,Double v2){
BigDecimal b1 = new BigDecimal(v1.toString());
BigDecimal b2 = new BigDecimal(v2.toString());
return b1.multiply(b2).doubleValue();
}
}
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