计算器问题-安卓编程

Question

我正在尝试设计一个简单的计算器，用作一两场比赛的记分牌。最终，我希望能够选择玩家的数量，让屏幕上出现那么多分数追踪器，能够使用触摸计算器进行加减（或除法或乘法），我让它在很大程度上起作用。

目前，它采用计算器显示中输入的文本，将其添加/减去我选择的玩家分数。

问题是试图让数字键显示在计算器显示部分。例如，我希望能够点击"1"，然后点击"0"，并在计算器中显示"10"。这应该很容易，因为我可以手动输入文本（使用android默认键盘），但我能得到的最接近的结果是一次只显示一个数字。。。

长话短说，我正在尝试让触摸板式计算器的数字按钮工作和显示。下面是我的主要项目代码。如果你需要我的布局代码，我也可以发布（用于ID引用）。

我知道这可能是一个简单的解决方案，但我发现的每一个教程要么过于复杂，要么不起作用。。。非常感谢您的帮助！

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));
                            }
                    }
            });

Answer 1

这个例子怎么样？

这是名为"CalculatorExample.java"的主类

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);
    }
}

这是XML文件（"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>

Answer 2

你不能有一个字符串，每次按下计算器上的按钮都可以附加到它吗？然后用新的字符串更新计算器显示？