问题
I'm trying to design a simple calculator for use as a scoreboard for a game or two. Ultimately, I want to be able to select the number of players, have that many score-trackers appear on screen, be able to use a the touch calculator to add or subtract (or divide or multiply) I got it to work for the most part.
Currently, it takes the text inputted in the calculator display, adds/subtracts/whatever that to the player score that I choose.
The problem is trying to get the numerical keys to show up in the calculator display part. For instance, I want to be able to hit "1" then "0" and have "10" appear in the calculator. It should have been easy, seeing as I am able to input text MANUALLY (using the android default keyboard), but the closest I can get is for only 1 number to show up at a time...
Long story short, I am trying to get a touch-pad type calculator's numerical buttons to work and display. Below is my main project code. If you need my layout code, I can post that as well (for references to IDs).
I know it's probably a simple solution, but every tutorial I find is either overly complicated or does not work... ANY help is greatly appreciated!
package com.MCalculator8.test;
import com.MCalculator8.test.R;
import android.app.Activity;
import android.app.AlertDialog;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.TextView;
public class MCalculator8Activity extends Activity {
private EditText player1name;
private EditText player2name;
private EditText player3name;
private EditText player4name;
private EditText player5name;
private EditText player6name;
private EditText player7name;
private EditText player1score;
private EditText player2score;
private EditText player3score;
private EditText player4score;
private EditText player5score;
private EditText player6score;
private EditText player7score;
private EditText input;
private TextView operator;
private MCalculator8Activity mContext;
// Called when the activity is first created.
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mContext = this;
setContentView(R.layout.main);
player1name = (EditText) findViewById(R.id.player1name);
player2name = (EditText) findViewById(R.id.player2name);
player3name = (EditText) findViewById(R.id.player3name);
player4name = (EditText) findViewById(R.id.player4name);
player5name = (EditText) findViewById(R.id.player5name);
player6name = (EditText) findViewById(R.id.player6name);
player7name = (EditText) findViewById(R.id.player7name);
input = (EditText) findViewById(R.id.input);
player1score = (EditText) findViewById(R.id.player1score);
player2score = (EditText) findViewById(R.id.player2score);
player3score = (EditText) findViewById(R.id.player3score);
player4score = (EditText) findViewById(R.id.player4score);
player5score = (EditText) findViewById(R.id.player5score);
player6score = (EditText) findViewById(R.id.player6score);
player7score = (EditText) findViewById(R.id.player7score);
operator = (TextView) findViewById(R.id.operator);
// We create an OnClick Event in each button.
Button plusButton = (Button) findViewById(R.id.add);
Button minusButton = (Button) findViewById(R.id.subtract);
Button multiplyButton = (Button) findViewById(R.id.multiply);
Button player1equals = (Button) findViewById(R.id.player1equals);
Button player2equals = (Button) findViewById(R.id.player2equals);
Button player3equals = (Button) findViewById(R.id.player3equals);
Button player4equals = (Button) findViewById(R.id.player4equals);
Button player5equals = (Button) findViewById(R.id.player5equals);
Button player6equals = (Button) findViewById(R.id.player6equals);
Button player7equals = (Button) findViewById(R.id.player7equals);
plusButton.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
operator.setText("+");
}
});
minusButton.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
operator.setText("-");
}
});
multiplyButton.setOnClickListener(new OnClickListener() {
public void onClick(View arg0) {
operator.setText("x");
}
});
player1equals.setOnClickListener(new OnClickListener() {
private AlertDialog show;
public void onClick(View arg0) {
if ((input.getText().length() == 0)
|| (input.getText().toString() == " ")) {
// || (input2.getText().length() == 0)
// || (input2.getText().toString() == " ")) {
show = new AlertDialog.Builder(mContext).setTitle("Error")
.setMessage("Some inputs are empty")
.setPositiveButton("OK", null).show();
} else if (operator.getText().equals("")) {
show = new AlertDialog.Builder(mContext).setTitle("Error")
.setMessage("Operator is null").setPositiveButton(
"OK", null).show();
} else if (operator.getText().equals("+")) {
double result = new Double(input.getText().toString())
+ new Double(player1score.getText().toString());
player1score.setText(Double.toString(result));
} else if (operator.getText().equals("-")) {
double result = new Double(player1score.getText().toString())
- new Double(input.getText().toString());
player1score.setText(Double.toString(result));
} else if (operator.getText().equals("x")) {
double result = new Double(input.getText().toString())
* new Double(player1score.getText().toString());
player1score.setText(Double.toString(result));
}
}
});
回答1:
How is this example?
Here is the Main Class called "CalculatorExample.java"
package com.calculatorExample;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
public class CalculatorExample extends Activity implements android.view.View.OnClickListener{
Button add, subtract, multiply, divide;
TextView firstInput, secondInput, output;
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
// Reference TextViews and Buttons
firstInput = (TextView) findViewById(R.id.firstIput);
secondInput = (TextView) findViewById(R.id.secondInput);
output = (TextView) findViewById(R.id.output);
add = (Button) findViewById(R.id.add);
subtract = (Button) findViewById(R.id.subtract);
multiply = (Button) findViewById(R.id.multiply);
divide = (Button) findViewById(R.id.divide);
// Set listeners for when buttons are pressed
add.setOnClickListener(this);
subtract.setOnClickListener(this);
multiply.setOnClickListener(this);
divide.setOnClickListener(this);
}
/**
* Switch statement to decide which button was pressed
*/
public void onClick(View arg0) {
// Get values from top two TextViews
double firstInputValue = Double.parseDouble(firstInput.getText().toString());
double secondInputValue = Double.parseDouble(secondInput.getText().toString());
// Initialise output
double outputValue = 0;
// Perform relevant operations
switch(arg0.getId()){
case R.id.add:
outputValue = firstInputValue + secondInputValue;
break;
case R.id.subtract:
outputValue = firstInputValue - secondInputValue;
break;
case R.id.multiply:
outputValue = firstInputValue * secondInputValue;
break;
case R.id.divide:
outputValue = firstInputValue / secondInputValue;
break;
}
// Add result to Running total stored in output TextView
outputValue += Double.parseDouble(output.getText().toString());
output.setText("" + outputValue);
}
}
And here is the XML file ("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"
>
<LinearLayout
android:weightSum="100"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<EditText
android:layout_weight="50"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/firstIput">
</EditText>
<EditText
android:layout_weight="50"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:id="@+id/secondInput">
</EditText>
</LinearLayout>
<LinearLayout
android:weightSum="100"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<Button
android:layout_weight="50"
android:text="+"
android:id="@+id/add"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</Button>
<Button
android:layout_weight="50"
android:text="-"
android:id="@+id/subtract"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</Button>
</LinearLayout>
<LinearLayout
android:weightSum="100"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
>
<Button
android:layout_weight="50"
android:text="X"
android:id="@+id/multiply"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</Button>
<Button
android:layout_weight="50"
android:text="/"
android:id="@+id/divide"
android:layout_width="fill_parent"
android:layout_height="wrap_content">
</Button>
</LinearLayout>
<EditText
android:text="0.0"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:id="@+id/output">
</EditText>
</LinearLayout>
回答2:
Couldn't you have a String that you could append to every time a button on the calculator is pressed? Then update the calculator display with the new String?
来源：https://stackoverflow.com/questions/9435041/calculator-problems-android-programming