我正在尝试构建一个简单的计算器。以下是活动文件：
package com.example.calcsimple;
import android.os.Bundle;
import android.annotation.SuppressLint;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import android.view.View.OnClickListener;
public class MainActivity extends Activity {
Button btnClr , btn0 , btn1 , btn2 , btn3 , btn4, btn5 , btn6 , btn7 , btn8 , btn9 , btnAdd , btnSub , btnMul , btnDiv , btnEq;
TextView textView1 ;
double i1 , i2 , result=0;
boolean newValue = false;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
textView1 = (TextView) findViewById(R.id.textView1);
btnClr = (Button) findViewById(R.id.btnClr);
btn0 = (Button) findViewById(R.id.btn0);
btn1 = (Button) findViewById(R.id.btn1);
btn2 = (Button) findViewById(R.id.btn2);
btn3 = (Button) findViewById(R.id.btn3);
btn4 = (Button) findViewById(R.id.btn4);
btn5 = (Button) findViewById(R.id.btn5);
btn6 = (Button) findViewById(R.id.btn6);
btn7 = (Button) findViewById(R.id.btn7);
btn8 = (Button) findViewById(R.id.btn8);
btn9 = (Button) findViewById(R.id.btn9);
btnAdd = (Button) findViewById(R.id.btnAdd);
btnSub = (Button) findViewById(R.id.btnSub);
btnMul = (Button) findViewById(R.id.btnMul);
btnDiv = (Button) findViewById(R.id.btnDiv);
btnEq = (Button) findViewById(R.id.btnEq);
btn0.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
textView1.append("0");
}
});
btn1.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("1");
else
textView1.setText(textView1.getText().toString() + "1");
newValue = false;
}
});
btn2.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("2");
else
textView1.setText(textView1.getText().toString() + "2");
newValue = false;
}
});
btn3.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("3");
else
textView1.setText(textView1.getText().toString() + "3");
newValue = false;
}
});
btn4.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("4");
else
textView1.setText(textView1.getText().toString() + "4");
newValue = false;
}
});
btn5.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("5");
else
textView1.setText(textView1.getText().toString() + "5");
newValue = false;
}
});
btn6.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("6");
else
textView1.setText(textView1.getText().toString() + "6");
newValue = false;
}
});
btn7.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("7");
else
textView1.setText(textView1.getText().toString() + "7");
newValue = false;
}
});
btn8.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("8");
else
textView1.setText(textView1.getText().toString() + "8");
newValue = false;
}
});
btn9.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
if(newValue == true)
textView1.setText("9");
else
textView1.setText(textView1.getText().toString() + "9");
newValue = false;
}
});
btnAdd.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
i1 = Double.parseDouble(textView1.getText().toString());
textView1.setText("");
result = result + i1;
textView1.setText(Double.toString(result));
newValue=true ;
}
});
btnSub.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
i1 = Double.parseDouble(textView1.getText().toString());
result = result - i1;
textView1.setText(Double.toString(result));
newValue=true ;
textView1.setText("");
}
});
btnMul.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
i1 = Double.parseDouble(textView1.getText().toString());
result = result * i1;
textView1.setText(Double.toString(result));
newValue=true ;
textView1.setText("");
}
});
btnDiv.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
i1 = Double.parseDouble(textView1.getText().toString());
result = result / i1;
textView1.setText(Double.toString(result));
newValue=true ;
textView1.setText("");
}
});
btnEq.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
textView1.setText(Double.toString(result));
}
});
btnClr.setOnClickListener(new OnClickListener(){
@Override
public void onClick(View v) {
textView1.setText("");
newValue=true;
result = 0 ;
i1=0;
}
});
}
}
以下是XML布局文件：
<AbsoluteLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent" >
<Button
android:id="@+id/btn1"
android:layout_width="44dp"
android:layout_height="wrap_content"
android:layout_x="6dp"
android:layout_y="109dp"
android:text="1" />
<Button
android:id="@+id/btn2"
android:layout_width="48dp"
android:layout_height="wrap_content"
android:layout_x="88dp"
android:layout_y="108dp"
android:text="2" />
<Button
android:id="@+id/btn3"
android:layout_width="44dp"
android:layout_height="wrap_content"
android:layout_x="174dp"
android:layout_y="106dp"
android:text="3" />
<Button
android:id="@+id/btn4"
android:layout_width="45dp"
android:layout_height="wrap_content"
android:layout_x="6dp"
android:layout_y="184dp"
android:text="4" />
<TextView
android:id="@+id/textView1"
android:layout_width="match_parent"
android:layout_height="30dp"
android:layout_x="0dp"
android:layout_y="4dp"
android:text="" />
<Button
android:id="@+id/btn5"
android:layout_width="45dp"
android:layout_height="wrap_content"
android:layout_x="92dp"
android:layout_y="186dp"
android:text="5" />
<Button
android:id="@+id/btn6"
android:layout_width="45dp"
android:layout_height="wrap_content"
android:layout_x="175dp"
android:layout_y="180dp"
android:text="6" />
<Button
android:id="@+id/btn7"
android:layout_width="44dp"
android:layout_height="wrap_content"
android:layout_x="9dp"
android:layout_y="261dp"
android:text="7" />
<Button
android:id="@+id/btn8"
android:layout_width="44dp"
android:layout_height="wrap_content"
android:layout_x="94dp"
android:layout_y="264dp"
android:text="8" />
<Button
android:id="@+id/btn9"
android:layout_width="46dp"
android:layout_height="wrap_content"
android:layout_x="176dp"
android:layout_y="263dp"
android:text="9" />
<Button
android:id="@+id/btn0"
android:layout_width="45dp"
android:layout_height="wrap_content"
android:layout_x="96dp"
android:layout_y="348dp"
android:text="0" />
<Button
android:id="@+id/btnAdd"
android:layout_width="45dp"
android:layout_height="wrap_content"
android:layout_x="248dp"
android:layout_y="105dp"
android:text="+" />
<Button
android:id="@+id/btnSub"
android:layout_width="43dp"
android:layout_height="wrap_content"
android:layout_x="249dp"
android:layout_y="181dp"
android:text="-" />
<Button
android:id="@+id/btnMul"
android:layout_width="43dp"
android:layout_height="wrap_content"
android:layout_x="248dp"
android:layout_y="267dp"
android:text="X" />
<Button
android:id="@+id/btnDiv"
android:layout_width="44dp"
android:layout_height="wrap_content"
android:layout_x="248dp"
android:layout_y="347dp"
android:text="/" />
<Button
android:id="@+id/btnEq"
android:layout_width="44dp"
android:layout_height="wrap_content"
android:layout_x="176dp"
android:layout_y="347dp"
android:text="=" />
<Button
android:id="@+id/btnClr"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_x="12dp"
android:layout_y="346dp"
android:text="Clear" />
</AbsoluteLayout>
现在的问题是我找不到任何方法来接收和存储用户的第二个操作数。
答案 0 :(得分：1)
从您的代码中可以看出，您的两个操作数都要输入到同一个TextView中。首先输入你的第一个操作数，然后按任意一个操作符然后在同一个TextView中第二个操作数将进入。此外，每个操作数似乎都由单个按钮处理，所以你只需要通过单击输入它们在按钮上。
首先，输入您的第一个操作数，单击一个运算符，然后单击第二个操作数，然后单击=。这应该适合你。
答案 1 :(得分：0)
'you can try this code..'
package com.example.showoff;
import java.util.ArrayList;
import android.os.Bundle;
import android.app.Activity;
import android.text.method.DigitsKeyListener;
import android.view.Menu;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class MainActivity extends Activity {
TextView edittest1;
Button one, two, three, four, five, six, seven, eight, nine, zero, add, sub, mul, div, cancel, equal;
ArrayList<Float> math = new ArrayList<Float>();
float m1;
float m2;
float temp;
int currentOperation = 0;
int nextOperation;
final static int ADD = 1;
final static int SUBTRACT = 2;
final static int MULTIPLY =3;
final static int DIVISION = 4;
final static int EQUALS = 0;
final static int CLEAR = 1;
final static int DONT_CLEAR = 0;
int clearDisplay = 0;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
edittest1 = (TextView) findViewById(R.id.edittest1);
one =(Button) findViewById(R.id.btnNum1Id);
two =(Button) findViewById(R.id.btnNum2Id);
three =(Button) findViewById(R.id.btnNum3Id);
four =(Button) findViewById(R.id.btnNum4Id);
five =(Button) findViewById(R.id.btnNum5Id);
six =(Button) findViewById(R.id.btnNum6Id);
seven =(Button) findViewById(R.id.btnNum7Id);
eight =(Button) findViewById(R.id.btnNum8Id);
nine =(Button) findViewById(R.id.btnNum9Id);
zero =(Button) findViewById(R.id.btnNum0Id);
add =(Button) findViewById(R.id.btnNumAddId);
sub =(Button) findViewById(R.id.btnNumSubId);
mul =(Button) findViewById(R.id.btnNumMulId);
div =(Button) findViewById(R.id.btnNumDivId);
cancel =(Button) findViewById(R.id.btnNumClearId);
equal =(Button) findViewById(R.id.btnNumEqualId);
edittest1.setKeyListener(DigitsKeyListener.getInstance(true,true));
registerListeners();
}
private void registerListeners() {
// TODO Auto-generated method stub
one.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("1");
}
});
two.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("2");
}
});
three.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("3");
}
});
four.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("4");
}
});
five.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("5");
}
});
six.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("6");
}
});
seven.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("7");
}
});
eight.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("8");
}
});
nine.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("9");
}
});
zero.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
if (clearDisplay == CLEAR) {
edittest1.setText("");
}
clearDisplay = DONT_CLEAR;
edittest1.append("0");
}
});
add.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
calcLogic(ADD);
}
}
);
sub.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
calcLogic(SUBTRACT);
}
});
mul.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
calcLogic(MULTIPLY);
}
});
div.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
calcLogic(DIVISION);
}
});
equal.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
calcLogic(EQUALS);
}
});
cancel.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
edittest1.setText("0");
m1 = 0;
m2 = 0;
math.removeAll(math);
currentOperation = 0;
nextOperation = 0;
}
});
}
private void calcLogic(int operator){
math.add(Float.parseFloat(edittest1.getText().toString()));
if (operator != EQUALS) {
nextOperation = operator;
}
else if (operator == EQUALS){
nextOperation = 0;
//operator=' ';
}
switch (currentOperation) {
case ADD:
m1 = math.get(0);
m2 = math.get(1);
math.removeAll(math);
math.add(m1 + m2);
edittest1.setText(String.format("%.3f", math.get(0)));
break;
case SUBTRACT:
m1 = math.get(0);
m2 = math.get(1);
math.removeAll(math);
math.add(m1 - m2);
edittest1.setText(String.format("%.3f", math.get(0)));
break;
case MULTIPLY:
m1 = math.get(0);
m2 = math.get(1);
math.removeAll(math);
math.add(m1 * m2);
edittest1.setText(String.format("%.3f", math.get(0)));
break;
case DIVISION:
m1 = math.get(0);
m2 = math.get(1);
math.removeAll(math);
math.add(m1 / m2);
edittest1.setText(String.format("%.3f", math.get(0)));
break;
}
clearDisplay = CLEAR;
currentOperation = nextOperation;
if (operator == EQUALS) {
m1 = 0;
m2 = 0;
math.removeAll(math);
}
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
}