java - 如何将字符串从包含字符和整数的变量转换为整数

Question

我正在学习 java 和 android SDK。为了学习属性，我构建了一个计算器(尚未完成)。在我的代码中，我使用 ImageView 标签来获取用户点击的按钮的值:

ImageView button = (ImageView) view;        
String buttonTag = button.getTag().toString(); 

xml:

<ImageView
                android:layout_width="80dp"
                android:layout_height="80dp"
                android:id="@+id/zero"
                android:layout_row="17"
                android:layout_column="1"
                android:tag="0"
                android:onClick="calcPad" />

ImageView 标签值是:“0”-“9”、“加号”/“减号”等。所以我将它转换为字符以获取数字并将其转换回整数:

char[] charTag = buttonTag.toCharArray();
for (int z=0; z < charTag.length; z++) { 
        if (charTag[z] == '0') {number = 0;}
        if (charTag[z] == '1') {number = 1;}
        ...
        if (charTag[z] == '9') {number = 9;}

我曾尝试使用“try”和“catch”，但应用程序崩溃了。这是我试图做的:

try{
     num = Integer.getInteger(buttonTag);

}  catch(NumberFormatException e) {
    Log.i("Exception", e.getMessage());
    switch(buttonTag) {
         case "Plus":
         .....
         default:
     }

}

我需要添加什么才能“处理”异常？我试图在 catch 中添加一个获取 buttonTag 值(即字符串)的开关，但仍然是同样的问题。

完整代码(没有 try/catch 部分):

 package com.example.idan.calculator;

import android.os.Bundle;
import android.support.design.widget.FloatingActionButton;
import android.support.design.widget.Snackbar;
import android.support.v7.app.AppCompatActivity;
import android.support.v7.widget.Toolbar;
import android.util.Log;
import android.view.View;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import java.io.IOException;


public class MainActivity extends AppCompatActivity {
    double  var1 = 0;           //holds the first number
    double  var2 = 0;           //holds the second number
    int     decimalPoint = 0;   //indicate if the user clicked on the (.)
    String  var1string="";      //for processing
    String  var2string="";      //for processing
    double  var1Array[]={0,0};  // the return value of var1doublemaker
    double  var2Array[]={0,0};  // the return value of var2doublemaker
    boolean mathAction = false; // indicate if the user clicked on a mathematical button
    int     mathType = 0;       // help me identify between + - * /
    char    mathValue = 'x';    // for the display
    double  result = 0;         // final result

    public double[] var1doubleMaker (String buttonTag, int decimalPoint) {
        if (decimalPoint == 1) {                            //need to add dot to string
            var1string = var1string + "." + buttonTag;
            var1 = Double.valueOf(var1string);
            decimalPoint = 0;                               // set back to 0
            var1Array[0] = var1;
            var1Array[1] = decimalPoint;
        } else {
            var1string = var1string + buttonTag;            // add the last number
            var1 = Double.valueOf(var1string);
            var1Array[0] = var1;
            var1Array[1] = decimalPoint;
        }
        return(var1Array);


    }
    public double[] var2doubleMaker (String buttonTag, int decimalPoint) {
        if (decimalPoint == 1) {
            var2string = var2string + "." + buttonTag;
            var2 = Double.valueOf(var2string);
            decimalPoint = 0;
            var2Array[0] = var2;
            var2Array[1] = decimalPoint;
        } else {
            var2string = var2string + buttonTag;
            var2 = Double.valueOf(var2string);
            var2Array[0] = var2;
            var2Array[1] = decimalPoint;
        }
        return(var2Array);


    }


    public void calcPad(View view) throws NumberFormatException{

        //check which button the user clicked on-
        //  first: get the ImageView by id
        ImageView button = (ImageView) view;                  // where the user clicked on
        String buttonTag = button.getTag().toString();       // hold the tag as string for the switch
        char[] charTag = buttonTag.toCharArray();
        int number = 111;                                       // 111 - just for initialization
        int num = 111;
/*
        try{
             num = Integer.getInteger(buttonTag);

        }  catch(NumberFormatException e) {
            Log.i("Exception", e.getMessage());

        }
        */
        Log.i("info - num value:", String.valueOf(num));
        //Log.i("info char", String.valueOf(charTag[0]));

        char numberToResolve = charTag[0];
        switch (numberToResolve)  {
            case '0':
                number = 0;
                break;
            case '1':
                number = 1;
                break;
            case '2':
                number = 2;
                break;
            case '3':
                number = 3;
                break;
            case '4':
                number = 4;
                break;
            case '5':
                number = 5;
                break;
            case '6':
                number = 6;
                break;
            case '7':
                number = 7;
                break;
            case '8':
                number = 8;
                break;
            case '9':
                number = 9;
                break;
            default:
                    Log.i("error", "cant resolve number from charTag[]");
        }


        //Log.i("info number value", String.valueOf(number));

        TextView textView = (TextView) findViewById(R.id.calcDisplay);  // create an object to print the button that the user clicked

        Log.i("info", buttonTag);

        // math
        if (buttonTag.length() > 1) {
            switch(buttonTag) {
                case "divid":
                    mathValue = '/';
                    mathAction = true;
                    mathType = 4;
                    break;
                case "multi":
                    mathValue = '*';
                    mathAction = true;
                    mathType = 3;
                    break;
                case "Plus":
                    mathValue = '+';
                    mathAction = true;
                    mathType = 1;
                    break;
                case "minus":
                    mathValue = '-';
                    mathAction = true;
                    mathType = 2;
                    break;
                case "dot":
                    decimalPoint = 1;
                case "equal":
                    if (mathType == 1) {
                        result = var1 + var2;
                    } else if (mathType == 2) {
                        result = var1 - var2;
                    } else if (mathType == 3) {
                        result = var1 * var2;
                    } else if (mathType == 4) {
                        result = var1 / var2;
                    }
                    String display = Double.toString(result);
                    textView.setText(display);
                    break;
                case "cc":
                    var1 = 0;
                    var2 = 0;
                    mathAction = false;
                    decimalPoint = 0;
                    result = 0;
                    var1string="";      //for processing
                    var2string="";
                    display = Double.toString(result);
                    textView.setText(display);
                    break;
                default:
                    Log.i("error", "cant resolve math type from buttonTag");
            }
        }

        //Log.i("info decimalpoint", String.valueOf(decimalPoint));


        if (number >= 0 && number <= 9 ) {
            // user clicked on a number
            //call doubleMaker
            if (mathAction) {
                //working on var2
                double[] var2temp = var2doubleMaker(buttonTag,decimalPoint);

                Double dd= var2temp[1];
                decimalPoint =  dd.intValue();      // set decimalPoint back to 0

                // display var1 + math + var2
                String display = Double.toString(var1) + Character.toString(mathValue) + Double.toString(var2temp[0]);

                textView.setText(display);
            } else {
                // working on var1
                double[] var1temp = var1doubleMaker(buttonTag,decimalPoint);

                Double d= var1temp[1];
                decimalPoint =  d.intValue();
                String display = Double.toString(var1temp[0]);

                textView.setText(display);
            }


        }

        Log.i("info - var1:", Double.toString(var1));
        Log.i("info - var2:", Double.toString(var2));
    }
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
        setSupportActionBar(toolbar);

        FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
        fab.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                Snackbar.make(view, "Replace with your own action", Snackbar.LENGTH_LONG)
                        .setAction("Action", null).show();
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings) {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }
}

Answer 1

你只需要将你的字符串传递给它:Integer.parseInt("string")。此方法帮助您从字符串转换为 int

 ImageView button = (ImageView) view;                
 String buttonTag = button.getTag().toString();
 int number = Integer.parseInt(buttonTag)