Tạo Caculator Pro

Từng khu vực:

1. Hiển thị toàn bộ các số người dùng đã nhập trước đó và đang chờ tính toán cho đến khi người nhập nhấp vào nút C để xóa

2. Khi người dùng nhập số, kết quả của bộ đệm sẽ được hiển thị

3. Giá trị bộ nhớ đệm sẽ được hiển thị ở vùng này

4. Nút tổ chức bộ nhớ đệm

5. Các nút khác

6. Nút để kích hoạt và hiển thị kết quả

7. Nút tính toán + - * /

8. Phím số

9. Trở về

Các trường hợp sử dụng TouchCalculator

Máy tính của chúng ta hỗ trợ các trường hợp sử dụng sau đây:

Tạo giao diện sử dụng main.xml

<?xml version="1.0" encoding="utf-8"?>

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"

    android:orientation="vertical"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent">

<TextView

    android:id="@+id/txtStack"

    android:layout_width="fill_parent"

    android:layout_height="wrap_content"

    android:textSize="15sp"

    android:gravity="right"

    android:layout_marginTop = "3sp"

    android:layout_marginLeft = "5sp"

    android:layout_marginRight = "5sp"/>

    <TextView

     android:id="@+id/txtInput"

     android:layout_width="fill_parent"

     android:layout_height="wrap_content"

     android:textSize="25sp"

     android:gravity="right"

     android:layout_marginLeft = "5sp"

    android:layout_marginRight = "5sp"/>

    <TextView

     android:id="@+id/txtMemory"

     android:layout_width="fill_parent"

     android:layout_height="wrap_content"

     android:textSize="15sp"

     android:gravity="left"

        android:layout_marginLeft = "5sp"

    android:layout_marginRight = "5sp"/>

<GridView xmlns:android="http://schemas.android.com/apk/res/android"

    android:id="@+id/grdButtons"

    android:layout_width="fill_parent"

    android:layout_height="fill_parent"

    android:columnWidth="90dp"

    android:numColumns="5"

    android:verticalSpacing="10dp"

    android:horizontalSpacing="10dp"

    android:stretchMode="columnWidth"

    android:gravity="center"/>

</LinearLayout>

Tạo nút bằng cách. Chuột phải layout>New Enum> 

KeypadButton.java

package by.QuangIT;

public enum KeypadButton {

MC("MC",KeypadButtonCategory.MEMORYBUFFER)

, MR("MR",KeypadButtonCategory.MEMORYBUFFER)

, MS("MS",KeypadButtonCategory.MEMORYBUFFER)

, M_ADD("M+",KeypadButtonCategory.MEMORYBUFFER)

, M_REMOVE("M-",KeypadButtonCategory.MEMORYBUFFER)

, BACKSPACE("<-",KeypadButtonCategory.CLEAR)

, CE("CE",KeypadButtonCategory.CLEAR)

, C("C",KeypadButtonCategory.CLEAR)

, ZERO("0",KeypadButtonCategory.NUMBER)

, ONE("1",KeypadButtonCategory.NUMBER)

, TWO("2",KeypadButtonCategory.NUMBER)

, THREE("3",KeypadButtonCategory.NUMBER)

, FOUR("4",KeypadButtonCategory.NUMBER)

, FIVE("5",KeypadButtonCategory.NUMBER)

, SIX("6",KeypadButtonCategory.NUMBER)

, SEVEN("7",KeypadButtonCategory.NUMBER)

, EIGHT("8",KeypadButtonCategory.NUMBER)

, NINE("9",KeypadButtonCategory.NUMBER)

, PLUS(" + ",KeypadButtonCategory.OPERATOR)

, MINUS(" - ",KeypadButtonCategory.OPERATOR)

, MULTIPLY(" * ",KeypadButtonCategory.OPERATOR)

, DIV(" / ",KeypadButtonCategory.OPERATOR)

, RECIPROC("1/x",KeypadButtonCategory.OTHER)

, DECIMAL_SEP(",",KeypadButtonCategory.OTHER)

, SIGN("±",KeypadButtonCategory.OTHER)

, SQRT("SQRT",KeypadButtonCategory.OTHER)

, PERCENT("%",KeypadButtonCategory.OTHER)

, CALCULATE("=",KeypadButtonCategory.RESULT)

, DUMMY("",KeypadButtonCategory.DUMMY);

 CharSequence mText; // Display Text

 KeypadButtonCategory mCategory;

  KeypadButton(CharSequence text,KeypadButtonCategory category) {

    mText = text;

    mCategory = category;

  }

  public CharSequence getText() {

    return mText;

  }

}

KeypadButtonCategory.java

package by.QuangIT;

public enum KeypadButtonCategory {

MEMORYBUFFER

  , NUMBER

  , OPERATOR

  , DUMMY

  , CLEAR

  , RESULT

  , OTHER

}

Tạo các nút trên bàn phím:

package by.QuangIT;

import android.content.Context;

import android.view.View;

import android.view.View.OnClickListener;

import android.view.ViewGroup;

import android.widget.BaseAdapter;

import android.widget.Button;

public class KeypadAdapter extends BaseAdapter {

private Context mContext;

// Declare button click listener variable

private OnClickListener mOnButtonClick;

public KeypadAdapter(Context c) {

mContext = c;

}

// Method to set button click listener variable

public void setOnButtonClickListener(OnClickListener listener) {

mOnButtonClick = listener;

}

public int getCount() {

return mButtons.length;

}

public Object getItem(int position) {

return mButtons[position];

}

public long getItemId(int position) {

return 0;

}

// create a new ButtonView for each item referenced by the Adapter

// create a new ButtonView for each item referenced by the Adapter

public View getView(int position, View convertView, ViewGroup parent) {

Button btn;

if (convertView == null) { // if it's not recycled, initialize some attributes

btn = new Button(mContext);

KeypadButton keypadButton = mButtons[position];

if (keypadButton != KeypadButton.DUMMY)

                     btn.setOnClickListener(mOnButtonClick);

//if(keypadButton != KeypadButton.CLEAR)

 //  btn.setBackgroundResource(R.drawable.keypadclear1);

// Set CalculatorButton enumeration as tag of the button so that we

// will use this information from our main view to identify what to do

btn.setTag(keypadButton);

} else {

btn = (Button) convertView;

}

btn.setText(mButtons[position].getText());

return btn;

}

// Create and populate keypad buttons array with CalculatorButton enum

// values

private KeypadButton[] mButtons = { KeypadButton.MC, KeypadButton.MR,

  KeypadButton.MS, KeypadButton.M_ADD, KeypadButton.M_REMOVE,

  KeypadButton.BACKSPACE, KeypadButton.CE, KeypadButton.C,

  KeypadButton.SIGN, KeypadButton.SQRT, KeypadButton.SEVEN,

  KeypadButton.EIGHT, KeypadButton.NINE, KeypadButton.DIV,

  KeypadButton.PERCENT, KeypadButton.FOUR, KeypadButton.FIVE,

  KeypadButton.SIX, KeypadButton.MULTIPLY, KeypadButton.RECIPROC,

  KeypadButton.ONE, KeypadButton.TWO, KeypadButton.THREE,

  KeypadButton.MINUS, KeypadButton.DECIMAL_SEP, KeypadButton.DUMMY,

  KeypadButton.ZERO, KeypadButton.DUMMY, KeypadButton.PLUS,

KeypadButton.CALCULATE };

}

Hiển thị bàn phím:

CaculatorProActivity.java

package by.QuangIT;

import java.text.DecimalFormat;

import java.text.NumberFormat;

import java.util.Iterator;

import java.util.Stack;

import android.app.Activity;

import android.os.Bundle;

import android.widget.AdapterView;

import android.widget.Button;

import android.widget.TextView;

import android.widget.AdapterView.OnItemClickListener;

import android.widget.GridView;

import android.view.View;

import android.view.View.OnClickListener;

public class CaculatorProActivity extends Activity {

GridView mKeypadGrid;

TextView userInputText;

TextView memoryStatText;

Stack<String> mInputStack;

Stack<String> mOperationStack;

KeypadAdapter mKeypadAdapter;

TextView mStackText;

boolean resetInput = false;

boolean hasFinalResult = false;

String mDecimalSeperator;

double memoryValue = Double.NaN;

/** Called when the activity is first created. */

@Override

public void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

DecimalFormat currencyFormatter = (DecimalFormat) NumberFormat

.getInstance();

char decimalSeperator = currencyFormatter.getDecimalFormatSymbols()

.getDecimalSeparator();

mDecimalSeperator = Character.toString(decimalSeperator);

setContentView(R.layout.main);

// Create the stack

mInputStack = new Stack<String>();

mOperationStack = new Stack<String>();

// Get reference to the keypad button GridView

mKeypadGrid = (GridView) findViewById(R.id.grdButtons);

// Get reference to the user input TextView

userInputText = (TextView) findViewById(R.id.txtInput);

userInputText.setText("0");

memoryStatText = (TextView) findViewById(R.id.txtMemory);

memoryStatText.setText("");

mStackText = (TextView) findViewById(R.id.txtStack);

// Create Keypad Adapter

mKeypadAdapter = new KeypadAdapter(this);

// Set adapter of the keypad grid

mKeypadGrid.setAdapter(mKeypadAdapter);

// Set button click listener of the keypad adapter

mKeypadAdapter.setOnButtonClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

Button btn = (Button) v;

// Get the KeypadButton value which is used to identify the

// keypad button from the Button's tag

KeypadButton keypadButton = (KeypadButton) btn.getTag();

// Process keypad button

ProcessKeypadInput(keypadButton);

}

});

mKeypadGrid.setOnItemClickListener(new OnItemClickListener() {

public void onItemClick(AdapterView<?> parent, View v,

int position, long id) {

}

});

}

private void ProcessKeypadInput(KeypadButton keypadButton) {

//Toast.makeText(this, keypadButton.getText(), Toast.LENGTH_SHORT).show();

String text = keypadButton.getText().toString();

String currentInput = userInputText.getText().toString();

int currentInputLen = currentInput.length();

String evalResult = null;

double userInputValue = Double.NaN;

switch (keypadButton) {

case BACKSPACE: // Handle backspace

// If has operand skip backspace

if (resetInput)

return;

int endIndex = currentInputLen - 1;

// There is one character at input so reset input to 0

if (endIndex < 1) {

userInputText.setText("0");

}

// Trim last character of the input text

else {

userInputText.setText(currentInput.subSequence(0, endIndex));

}

break;

case SIGN: // Handle -/+ sign

// input has text and is different than initial value 0

if (currentInputLen > 0 && currentInput != "0") {

// Already has (-) sign. Remove that sign

if (currentInput.charAt(0) == '-') {

userInputText.setText(currentInput.subSequence(1,

currentInputLen));

}

// Prepend (-) sign

else {

userInputText.setText("-" + currentInput.toString());

}

}

break;

case CE: // Handle clear input

userInputText.setText("0");

break;

case C: // Handle clear input and stack

userInputText.setText("0");

clearStacks();

break;

case DECIMAL_SEP: // Handle decimal seperator

if (hasFinalResult || resetInput) {

userInputText.setText("0" + mDecimalSeperator);

hasFinalResult = false;

resetInput = false;

} else if (currentInput.contains("."))

return;

else

userInputText.append(mDecimalSeperator);

break;

case DIV:

case PLUS:

case MINUS:

case MULTIPLY:

if (resetInput) {

mInputStack.pop();

mOperationStack.pop();

} else {

if (currentInput.charAt(0) == '-') {

mInputStack.add("(" + currentInput + ")");

} else {

mInputStack.add(currentInput);

}

mOperationStack.add(currentInput);

}

mInputStack.add(text);

mOperationStack.add(text);

dumpInputStack();

evalResult = evaluateResult(false);

if (evalResult != null)

userInputText.setText(evalResult);

resetInput = true;

break;

case CALCULATE:

if (mOperationStack.size() == 0)

break;

mOperationStack.add(currentInput);

evalResult = evaluateResult(true);

if (evalResult != null) {

clearStacks();

userInputText.setText(evalResult);

resetInput = false;

hasFinalResult = true;

}

break;

case M_ADD: // Add user input value to memory buffer

userInputValue = tryParseUserInput();

if (Double.isNaN(userInputValue))

return;

if (Double.isNaN(memoryValue))

memoryValue = 0;

memoryValue += userInputValue;

displayMemoryStat();

hasFinalResult = true;

break;

case M_REMOVE: // Subtract user input value to memory buffer

userInputValue = tryParseUserInput();

if (Double.isNaN(userInputValue))

return;

if (Double.isNaN(memoryValue))

memoryValue = 0;

memoryValue -= userInputValue;

displayMemoryStat();

hasFinalResult = true;

break;

case MC: // Reset memory buffer to 0

memoryValue = Double.NaN;

displayMemoryStat();

break;

case MR: // Read memoryBuffer value

if (Double.isNaN(memoryValue))

return;

userInputText.setText(doubleToString(memoryValue));

displayMemoryStat();

break;

case MS: // Set memoryBuffer value to user input

userInputValue = tryParseUserInput();

if (Double.isNaN(userInputValue))

return;

memoryValue = userInputValue;

displayMemoryStat();

hasFinalResult = true;

break;

default:

if (Character.isDigit(text.charAt(0))) {

if (currentInput.equals("0") || resetInput || hasFinalResult) {

userInputText.setText(text);

resetInput = false;

hasFinalResult = false;

} else {

userInputText.append(text);

resetInput = false;

}

}

break;

}

}

private void clearStacks() {

mInputStack.clear();

mOperationStack.clear();

mStackText.setText("");

}

private void dumpInputStack() {

Iterator<String> it = mInputStack.iterator();

StringBuilder sb = new StringBuilder();

while (it.hasNext()) {

CharSequence iValue = it.next();

sb.append(iValue);

}

mStackText.setText(sb.toString());

}

private String evaluateResult(boolean requestedByUser) {

if ((!requestedByUser && mOperationStack.size() != 4)

|| (requestedByUser && mOperationStack.size() != 3))

return null;

String left = mOperationStack.get(0);

String operator = mOperationStack.get(1);

String right = mOperationStack.get(2);

String tmp = null;

if (!requestedByUser)

tmp = mOperationStack.get(3);

double leftVal = Double.parseDouble(left.toString());

double rightVal = Double.parseDouble(right.toString());

double result = Double.NaN;

if (operator.equals(KeypadButton.DIV.getText())) {

result = leftVal / rightVal;

} else if (operator.equals(KeypadButton.MULTIPLY.getText())) {

result = leftVal * rightVal;

} else if (operator.equals(KeypadButton.PLUS.getText())) {

result = leftVal + rightVal;

} else if (operator.equals(KeypadButton.MINUS.getText())) {

result = leftVal - rightVal;

}

String resultStr = doubleToString(result);

if (resultStr == null)

return null;

mOperationStack.clear();

if (!requestedByUser) {

mOperationStack.add(resultStr);

mOperationStack.add(tmp);

}

return resultStr;

}

private String doubleToString(double value) {

if (Double.isNaN(value))

return null;

long longVal = (long) value;

if (longVal == value)

return Long.toString(longVal);

else

return Double.toString(value);

}

private double tryParseUserInput() {

String inputStr = userInputText.getText().toString();

double result = Double.NaN;

try {

result = Double.parseDouble(inputStr);

} catch (NumberFormatException nfe) {

}

return result;

}

private void displayMemoryStat() {

if (Double.isNaN(memoryValue)) {

memoryStatText.setText("");

} else {

memoryStatText.setText("M = " + doubleToString(memoryValue));

}

}

}