计算长度、面积和温度时两个纺纱机相乘的java问题

uajslkp6  于 2021-07-03  发布在  Java
关注(0)|答案(1)|浏览(359)

我遇到的问题是应用程序无法执行我设计的任务。我成功地运行了这个应用程序，但是当我单击任何一个微调器时，列表根本就没有下降。所有的纺纱机都没有React，我也不知道问题出在哪里。我想尽一切办法来解决这个问题，但我做不到。我运行代码很多次都没有收到错误消息，但是微调器仍然不工作。有人能帮忙吗？这个应用程序可以转换长度，面积和温度。
string.xml文件

<resources>
    <string name="spinner_1">From</string>
    <string name="spinner_2">To</string>
    <string-array name="conversion_type">
        <item>Length</item>
        <item>Area</item>
        <item>Temperature</item>
    </string-array>
    <string-array name="area">
        <item>Square kilometre</item>
        <item>Square metre</item>
        <item>Square yard</item>
        <item>Square foot</item>
        <item>Square inch</item>
        <item>Square mile</item>
        <item>Hectare</item>
        <item>Acre</item>
    </string-array>

    <string-array name="length">
        <item>Kilometre</item>
        <item>Metre</item>
        <item>Centimetre</item>
        <item>Millimetre</item>
        <item>Micrometer</item>
        <item>Mile</item>
        <item>Yard</item>
        <item>Foot</item>
        <item>Inch</item>
        <item>Nautical Mile</item>
    </string-array>

    <string-array name="temperature">
        <item>Celsius</item>
        <item>Kelvin</item>
        <item>Fahrenheit</item>
    </string-array>
</resources>

活动\u main.xml

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    app:layout_behavior="@string/appbar_scrolling_view_behavior"
    tools:context=".MainActivity">
    <TextView
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:text="Conversion Type"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="12dp"
        android:textSize="16sp"
        android:textColor="#607D8B"
        android:textStyle="bold"
        android:id="@+id/text"/>
    <LinearLayout
        android:layout_below="@+id/text"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical"
        android:layout_marginTop="10dp"
        android:layout_marginLeft="8dp"
        android:id="@+id/first_linear"
        android:layout_marginRight="8dp">

        <TextView
            android:layout_width="match_parent"
            android:layout_height="1dp"
            android:layout_marginLeft="4dp"
            android:layout_marginRight="4dp"
            android:layout_marginBottom="20dp"
            android:background="#cbcbcb"/>
        <Spinner
            android:id="@+id/conversion_type"
            android:layout_weight="1"
            android:layout_width="fill_parent"
            android:layout_marginLeft="4dp"
            android:layout_marginRight="4dp"
            android:layout_height="wrap_content" />

        <TextView
            android:layout_width="match_parent"
            android:layout_marginTop="20dp"
            android:layout_marginLeft="4dp"
            android:layout_marginRight="4dp"
            android:layout_height="1dp"
            android:id="@+id/text_some"
            android:background="#cbcbcb"/>
    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_below="@id/first_linear"
        android:layout_height="wrap_content"
        android:layout_marginRight="8dp"
        android:id="@+id/second_linear"
        android:layout_marginLeft="8dp"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/text_from"
                android:layout_marginTop="20dp"
                android:layout_marginLeft="4dp"
                android:text="From"
                android:textStyle="bold"
                android:textSize="16sp"
                android:textColor="#607D8B"
                android:layout_below="@id/first_linear"/>

            <Spinner
                android:id="@+id/from_spinner"
                android:layout_weight="1"
                android:layout_width="match_parent"
                android:layout_marginLeft="30dp"
                android:layout_marginRight="30dp"
                android:layout_marginTop="18dp"
                android:layout_marginBottom="20dp"
                android:layout_height="wrap_content" />
        </LinearLayout>
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content">
            <EditText
                android:hint="edit_text_from"
                android:id="@+id/from_edit"
                android:layout_width="0dp"
                android:layout_weight="3"
                android:layout_height="wrap_content"
                android:layout_marginTop="15dp"
                android:inputType="numberSigned|numberDecimal"
                android:layout_marginLeft="30dp" />
            <Button
                android:layout_width="0dp"
                android:layout_height="45dp"
                android:layout_gravity="bottom"
                android:layout_weight="1"
                android:text="Clear"
                android:layout_marginBottom="2dp"
                android:id="@+id/clear_text_unit"
                android:onClick="clear_unit"
                />
        </LinearLayout>
    </LinearLayout>
    <TextView
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:layout_marginTop="30dp"
        android:id="@+id/third_text"
        android:layout_below="@+id/second_linear"
        android:layout_marginBottom="0dp"
        android:background="#FFCBCBCB"/>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:layout_below="@id/third_text"
        android:id="@+id/fourth_linear"
        android:layout_marginLeft="8dp"
        android:layout_marginRight="8dp"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:orientation="horizontal">
            <TextView
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:id="@+id/text_to"
                android:layout_marginTop="20dp"
                android:layout_marginLeft="6dp"
                android:text="To"
                android:textStyle="bold"
                android:textSize="16sp"
                android:textColor="#607D8B" />

            <Spinner
                android:id="@+id/to_spinner"
                android:layout_weight="1"
                android:layout_width="match_parent"
                android:layout_marginLeft="50dp"
                android:layout_marginRight="30dp"
                android:layout_marginTop="18dp"
                android:layout_marginBottom="10dp"
                android:layout_height="wrap_content" />
        </LinearLayout>
        <TextView
            android:layout_width="match_parent"
            android:layout_height="wrap_content"
            android:layout_marginLeft="33dp"
            android:background="#e6e5e5"
            android:paddingLeft="10dp"
            android:paddingBottom="5dp"
            android:paddingTop="5dp"
            android:maxLines="1"
            android:scrollHorizontally="true"
            android:layout_marginTop="20dp"
            android:id="@+id/to_text"
            android:textSize="20sp"
            android:textColor="#000"
            android:layout_marginRight="30dp"/>
    </LinearLayout>

    <TextView
        android:layout_width="match_parent"
        android:layout_height="1dp"
        android:layout_marginLeft="16dp"
        android:layout_marginRight="16dp"
        android:layout_marginTop="40dp"
        android:layout_below="@+id/fourth_linear"
        android:layout_marginBottom="10dp"
        android:background="#FFCBCBCB"/>
</RelativeLayout>

mainactivity.java文件

package com.example.learnspinner;

import androidx.appcompat.app.AppCompatActivity;

import android.os.Bundle;
import android.os.Handler;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Spinner;
import android.widget.TextView;
import android.widget.Toast;

import java.math.BigDecimal;
import java.math.RoundingMode;
import java.text.DecimalFormat;
import java.text.NumberFormat;

public class MainActivity extends AppCompatActivity {
    int spinner_cycle_pos = 0, spinner_duration_pos = 0;

    Spinner from_spinner, to_spinner, conversion_type, duration_spinner, cycle_spinner;
    String from_spinner_string, to_spinner_string, choice_spinner;
    int from_spinner_position, to_spinner_position, choice_spinner_pos;
    Button btnConvert;
    TextView result;
    EditText quantity;
    ArrayAdapter<CharSequence> adapter_length, adapter_temperature, adapter_area;

    BigDecimal[][] array = {{new BigDecimal("1"), new BigDecimal("1000000.0"), new BigDecimal("1195990.05"), new BigDecimal("10763910.4"), new BigDecimal("1550000000"), new BigDecimal("0.386102"), new BigDecimal("100"), new BigDecimal("247.105")},
            {new BigDecimal("1"), new BigDecimal("0.125"), new BigDecimal("0.000122073125"), new BigDecimal("0.00000011920992"), new BigDecimal("0.0000000001164153"), new BigDecimal("0.0000000000001136868377"), new BigDecimal("0.000000000000001110223024")},
            {new BigDecimal("1"), new BigDecimal("0.001"), new BigDecimal("0.000239006"), new BigDecimal("0.00000027778"), new BigDecimal("0.737562")},
            {new BigDecimal("1"), new BigDecimal("0.001"), new BigDecimal("0.000001"), new BigDecimal("0.000000001")},
            {new BigDecimal("1"), new BigDecimal("1000"), new BigDecimal("1000000"), new BigDecimal("1000000000"), new BigDecimal("1000000000000"), new BigDecimal("157.473"), new BigDecimal("2204.62"), new BigDecimal("35274")},
            {new BigDecimal("1"), new BigDecimal("1000"), new BigDecimal("100000"), new BigDecimal("10000000000"), new BigDecimal("10000000000000"), new BigDecimal("0.621371"), new BigDecimal("1093.61"), new BigDecimal("3280.84"), new BigDecimal("39370.1"), new BigDecimal("0.539953")},
            {new BigDecimal("1"), new BigDecimal("1.1111111300619"), new BigDecimal("0.0174533"), new BigDecimal("17.453300")},
            {new BigDecimal("1"), new BigDecimal("1.01325"), new BigDecimal("101325"), new BigDecimal("760")},
            {new BigDecimal("1"), new BigDecimal("1.46667"), new BigDecimal("0.44704"), new BigDecimal("1.60934"), new BigDecimal("0.868976")},
            {},  // keep blank for temperature
            {new BigDecimal("1"), new BigDecimal("0.001"), new BigDecimal("0.000016667"), new BigDecimal("0.00000027778"), new BigDecimal("0.000000011574"), new BigDecimal("0.0000000016534"), new BigDecimal("0.00000000038052"), new BigDecimal("0.00000000003171"), new BigDecimal("0.000000000003171"), new BigDecimal("0.0000000000003171")},
            {new BigDecimal("1"), new BigDecimal("1000"), new BigDecimal("0.219969"), new BigDecimal("0.879877"), new BigDecimal("3.51951"), new BigDecimal("0.0353147"), new BigDecimal("61.0237"), new BigDecimal("61023.7")}};
    String val = "0";

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

    }

    private void initialise_adapters() {
        adapter_temperature = ArrayAdapter.createFromResource(getApplication(), R.array.temperature, android.R.layout.simple_spinner_item);
        adapter_length = ArrayAdapter.createFromResource(getApplication(), R.array.length, android.R.layout.simple_spinner_item);
        adapter_area = ArrayAdapter.createFromResource(getApplication(), R.array.area, android.R.layout.simple_spinner_item);

    }

    private void unit_converter() {
        from_spinner = findViewById(R.id.from_spinner);
        to_spinner = findViewById(R.id.to_spinner);
        result = findViewById(R.id.to_text);
        quantity = findViewById(R.id.from_edit);
        conversion_type = (Spinner) findViewById(R.id.conversion_type);
        // Initialise the main spinner
        // Create an ArrayAdapter using the string array and a default spinner layout
        ArrayAdapter<CharSequence> adapter = ArrayAdapter.createFromResource(getApplication(), R.array.conversion_type, android.R.layout.simple_spinner_item);
        // Specify the layout to use when the list of choices appears
        adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        // Apply the adapter to the spinner
        conversion_type.setAdapter(adapter);
        conversion_type.setOnItemSelectedListener(new spinner());

        from_spinner = (Spinner) findViewById(R.id.from_spinner);
        to_spinner = (Spinner) findViewById(R.id.to_spinner);

        initialise_adapters();

        //initally set default to  area adapter
        adapter_area.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        from_spinner.setAdapter(adapter_area);
        to_spinner.setAdapter(adapter_area);
        from_spinner_string = "Square kilometer";
        to_spinner_string = "Square kilometer";
        choice_spinner = "Area";

        //Default values
        from_spinner_position = 0;
        to_spinner_position = 0;
        choice_spinner_pos = 0;
        int spinner_cycle_pos = 0, spinner_duration_pos = 0;

        from_spinner.setOnItemSelectedListener(new spinner());
        to_spinner.setOnItemSelectedListener(new spinner());

        quantity.addTextChangedListener(new TextWatcher() {
            @Override
            public void onTextChanged(CharSequence s, int start, int before, int count) {
            }

            @Override
            public void beforeTextChanged(CharSequence s, int start, int count, int after) {
            }

            @Override
            public void afterTextChanged(Editable s) {
                val = s.toString();
                int flag = 0;
                if (val.equals("")) {
                    flag = 1;
                    val = "0";
                }
                if (val.equals("-") || val.equals(".")) flag = 1;
                if (choice_spinner.equals("Temperature")) {
                    if (flag == 0) {
                        double celcius = Double.parseDouble(val);
                        if (from_spinner_position == 2) {
                            celcius = celcius - Double.parseDouble("32");
                            celcius = celcius * Double.parseDouble("0.55555");
                        } else if (from_spinner_position == 1)
                            celcius = celcius - Double.parseDouble("273.15");

                        if (to_spinner_position == 2) {
                            celcius = celcius * Double.parseDouble("1.8");
                            celcius = celcius + Double.parseDouble("32");
                        } else if (to_spinner_position == 1)
                            celcius = celcius + Double.parseDouble("273.15");
                        print_exponent(result, celcius);
                    } else {
                        result.setText("");
                    }

                } else {
                    if (flag == 0) {
                        double temp = Double.parseDouble(val);
                        temp = temp / Double.parseDouble(array[choice_spinner_pos][from_spinner_position].toString());
                        temp = temp * Double.parseDouble(array[choice_spinner_pos][to_spinner_position].toString());
                        temp = temp / Double.parseDouble(array[choice_spinner_pos][0].toString());
                        print_exponent(result, temp);
                    } else {
                        result.setText("");
                    }
                }
            }
        });

    }

    //Method to print the numbers in exponent form
    public void print_exponent(TextView view, double temp) {
        String temp1 = "" + temp;
        String temp2 = "";
        int bds = 0;
        for (char c : temp1.toCharArray()) {
            if (c == 'E') {
                temp2 += " e ";
                bds = 1;
            } else {
                if (bds == 1) {
                    if (c == '-')
                        temp2 += c;
                    else
                        temp2 = temp2 + "+" + c;
                } else
                    temp2 += c;
                bds = 0;
            }
        }
        view.setText(temp2);
    }

    //This method takes a big decimal number and convert that to the exponent from and scale is mantissa
    private static String format(BigDecimal x, int scale) {
        NumberFormat formatter = new DecimalFormat("0.0E0");
        formatter.setRoundingMode(RoundingMode.HALF_UP);
        formatter.setMinimumFractionDigits(scale);
        return formatter.format(x);
    }

    //Spinner class to select spinner and also add gender
    class spinner implements AdapterView.OnItemSelectedListener {

        @Override
        public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
            if (parent.getId() == R.id.conversion_type) {

                quantity.getText().clear();
                result.setText("");
                choice_spinner = parent.getItemAtPosition(position).toString();
                choice_spinner_pos = position;
                from_spinner.setEnabled(true);
                to_spinner.setEnabled(true);
                if (choice_spinner.equals("Area") == true) {
                    adapter_area.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    from_spinner.setAdapter(adapter_area);
                    to_spinner.setAdapter(adapter_area);
                } else if (choice_spinner.equals("Length") == true) {
                    adapter_length.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    from_spinner.setAdapter(adapter_length);
                    to_spinner.setAdapter(adapter_length);
                } else if (choice_spinner.equals("Temperature") == true) {
                    adapter_temperature.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
                    from_spinner.setAdapter(adapter_temperature);
                    to_spinner.setAdapter(adapter_temperature);
                } else if (parent.getId() == R.id.from_spinner) {
                    quantity.getText().clear();
                    result.setText("");
                    from_spinner_string = parent.getItemAtPosition(position).toString();
                    from_spinner_position = position;
                }
            }
        }

        @Override
        public void onNothingSelected(AdapterView<?> parent) {
            Toast.makeText(getApplicationContext(), "Please Select a category", Toast.LENGTH_SHORT).show();
            from_spinner.setEnabled(false);
            to_spinner.setEnabled(false);
        }

        public void clear_unit (View view){
            quantity.setText("");
            result.setText("");
            val = "";
        }
    }
}
JavaandroidArrayListandroid-studioandroid-spinner

1条答案

按热度按时间
lvjbypge

lvjbypge1#

根本原因
在 MainActivity ，的 unit_converter() 方法负责初始化 Spinner ，设置适配器，为 Spinner ，但您忘记在活动启动时调用此方法。
解决方案
打电话给 unit_converter() 方法。

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    unit_converter();
}

更新
当用户选择 from_spinner 以及 to_spinner ，不更新 from_spinner_position 以及 to_spinner_position 价值观。将代码更改为：

@Override
public void onItemSelected(AdapterView<?> parent, View view, int position, long id) {
    if (parent.getId() == R.id.conversion_type) {
        quantity.getText().clear();
        result.setText("");
        choice_spinner = parent.getItemAtPosition(position).toString();
        choice_spinner_pos = position;
        from_spinner.setEnabled(true);
        to_spinner.setEnabled(true);
        if (choice_spinner.equals("Area") == true) {
            adapter_area.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            from_spinner.setAdapter(adapter_area);
            to_spinner.setAdapter(adapter_area);
        } else if (choice_spinner.equals("Length") == true) {
            adapter_length.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            from_spinner.setAdapter(adapter_length);
            to_spinner.setAdapter(adapter_length);
        } else if (choice_spinner.equals("Temperature") == true) {
            adapter_temperature.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
            from_spinner.setAdapter(adapter_temperature);
            to_spinner.setAdapter(adapter_temperature);
        } else if (parent.getId() == R.id.from_spinner) {
            quantity.getText().clear();
            result.setText("");
            from_spinner_string = parent.getItemAtPosition(position).toString();
            from_spinner_position = position;
        }
    } else if (parent.getId() == R.id.from_spinner) {
        from_spinner_position = position;
    } else if (parent.getId() == R.id.to_spinner) {
        to_spinner_position = position;
    }
}
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