我要创建一个可以在Farhenheit和Celsius之间进行转换的应用程序，还可以实现一个显示接下来的5个温度及其相应转换的下拉菜单（微调器）。
import android.app.Activity;
import android.net.Uri;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.EditText;
import android.widget.RadioButton;
import android.widget.Button;
import android.widget.Spinner;
import java.text.DecimalFormat;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends Activity implements View.OnClickListener {
private EditText temp;
private RadioButton toC;
private RadioButton toF;
private Button ConvertButton;
private Spinner nextTempsSpinner;
private String tempText;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//Assigning the private Java variables to their XML counterparts
temp = (EditText) findViewById(R.id.editTemperature); //Text box where user enters temperature
toC = (RadioButton) findViewById(R.id.FtoC); //Radio Button user selects so that temperature will be interpreted as Fahrenheit and returned as Celsius
toF = (RadioButton) findViewById(R.id.CtoF); //Radio Button user selects so that temperature will be interpreted as Fahrenheit and returned as Celsius
ConvertButton = (Button) findViewById(R.id.GetConversion); //Button user will click to get the conversion
nextTempsSpinner = (Spinner) findViewById(R.id.spinMyTemps); //Spinner is the drop down menu where the next 5 conversions will appear
ConvertButton.setOnClickListener(this);
}
@Override
public void onClick(View v) {
Double temporary, answer, temporaryTemperature;
String goingFrom = null; //Adding these so that we can use these strings in the dropdown spinner
String goingTo = null;
double value = Double.valueOf(temp.getText().toString());
if (toC.isChecked()) // If the radio button for converting from Fahrenheit to Celsius is selected this conversion will happen
{
value = UnitConverter.FahrenheitToCelsius(value);
goingFrom = "F";
goingTo = "C";
} else if (toF.isChecked()) // If the radio button for converting from Celsius to Fahrenheit is selected this conversion will happen
{
value = UnitConverter.CelsiusToFahrenheit(value);
goingFrom = "C";
goingTo = "F";
}
temp.setText(Double.valueOf(value).toString());
DecimalFormat twoDecimalFormat = new DecimalFormat("#.##");
temporaryTemperature = Double.parseDouble(String.valueOf(temp));
//Creating ArrayAdapter
List<String> listOfTemps = new ArrayList<String>();
ArrayAdapter getTempAdapter = new ArrayAdapter(this,
android.R.layout.simple_spinner_item, listOfTemps);
getTempAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
for (int i = 0; i < 5; i++) {
answer = Double.parseDouble(twoDecimalFormat.format(temp));
temporary = temporaryTemperature + i;
tempText = temporary.toString();
tempText = tempText + " " + goingFrom + " = ";
tempText = tempText + answer.toString();
tempText = tempText + " " + goingTo;
listOfTemps.add(tempText);
}
nextTempsSpinner.setAdapter(getTempAdapter);
}
}
是的，我确实有一个名为UnitConverter的Java文件，它没有什么特别的，只是这个
public class UnitConverter {
public static double CelsiusToFahrenheit(double c){
return 32+c*9/5;
}
public static double FahrenheitToCelsius(double f){
return (f-32)*5/9;
}
}
转换部分肯定有效，单选按钮和转换按钮也是如此。在onClick方法的某个地方，因为我编写了微调器，它似乎已经变得混乱，现在整个应用程序崩溃了。谢谢你的帮助。
编辑：logcat信息如下：
08-13 15:30:31.557 2398-2398/com.aly.converttemps I/art: Not late-enabling -Xcheck:jni (already on)
[ 08-13 15:30:31.610 1580: 1601 D/ ]
HostConnection::get() New Host Connection established 0x7f0863664ec0, tid 1601
08-13 15:30:31.632 2398-2398/com.aly.converttemps W/System: ClassLoader referenced unknown path: /data/app/com.aly.converttemps-2/lib/x86_64
08-13 15:30:36.881 2398-2398/com.aly.converttemps W/System: ClassLoader referenced unknown path: /data/app/com.aly.converttemps-2/lib/x86_64
08-13 15:30:37.106 2398-2548/com.aly.converttemps D/OpenGLRenderer: Use EGL_SWAP_BEHAVIOR_PRESERVED: true
[ 08-13 15:30:37.113 2398: 2398 D/ ]
HostConnection::get() New Host Connection established 0x7f086f9941c0, tid 2398
[ 08-13 15:30:37.152 2398: 2548 D/ ]
HostConnection::get() New Host Connection established 0x7f086f994440, tid 2548
08-13 15:30:37.163 2398-2548/com.aly.converttemps I/OpenGLRenderer: Initialized EGL, version 1.4
[ 08-13 15:30:37.198 1209: 2251 D/ ]
HostConnection::get() New Host Connection established 0x7f4b63d56500, tid 2251
08-13 15:30:45.585 2398-2398/com.aly.converttemps D/AndroidRuntime: Shutting down VM
--------- beginning of crash
08-13 15:30:45.586 2398-2398/com.aly.converttemps E/AndroidRuntime: FATAL EXCEPTION: main
Process: com.aly.converttemps, PID: 2398
java.lang.NumberFormatException: Invalid double: "android.widget.EditText{1495b6d VFED..CL. .F....ID 42,42-592,144 #7f0b0003 app:id/editTemperature}"
at java.lang.StringToReal.invalidReal(StringToReal.java:63)
at java.lang.StringToReal.initialParse(StringToReal.java:114)
at java.lang.StringToReal.parseDouble(StringToReal.java:282)
at java.lang.Double.parseDouble(Double.java:301)
at com.aly.converttemps.MainActivity.onClick(MainActivity.java:75)
at android.view.View.performClick(View.java:5198)
at android.view.View$PerformClick.run(View.java:21147)
at android.os.Handler.handleCallback(Handler.java:739)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:148)
at android.app.ActivityThread.main(ActivityThread.java:5417)
at java.lang.reflect.Method.invoke(Native Method)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:726)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:616)
答案 0 :(得分：3)
您正在parseDouble（String）中将editText对象的引用作为String传递。
改变：
temporaryTemperature = Double.parseDouble(String.valueOf(temp));
到：
temporaryTemperature = Double.parseDouble(temp.getText().toString());
或：
temporaryTemperature = Double.valueOf(temp.getText().toString())
答案 1 :(得分：1)
看看这行代码：
temporaryTemperature = Double.parseDouble(String.valueOf(temp));
变量temp声明为：
private EditText temp;
请注意，temp是EditText。匹配此调用的String.valueOf()唯一版本是the one which takes an Object parameter。这与调用temp.toString()相同，后者打印类名和有关EditText对象的其他信息。
您需要检索用户输入的文字：
temporaryTemperature = Double.parseDouble(temp.getText().toString());