我正在努力奋斗以克服空的editText问题。 没有语法错误，但应用程序意外停止。
我不确定问题是来自侦听器还是IF循环。但是除了空的editText异常之外，计算器工作正常。
谢谢！
这是我的XML：
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
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"
tools:context="com.rayana.calculator.MainActivity" >
<TextView
android:id="@+id/textView3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentLeft="true"
android:layout_below="@+id/button1"
android:layout_marginTop="39dp"
android:text="Result ="
android:textAppearance="?android:attr/textAppearanceLarge" />
<TextView
android:id="@+id/textView2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/button1"
android:layout_alignLeft="@+id/button1"
android:layout_marginBottom="31dp"
android:text="B =" />
<TextView
android:id="@+id/textView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBottom="@+id/editText1"
android:layout_alignLeft="@+id/textView2"
android:text="A =" />
<EditText
android:id="@+id/editText1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/editText2"
android:layout_alignLeft="@+id/editText2"
android:layout_marginBottom="45dp"
android:ems="10"
android:inputType="numberDecimal" />
<EditText
android:id="@+id/editText2"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignBaseline="@+id/textView2"
android:layout_alignBottom="@+id/textView2"
android:layout_alignLeft="@+id/button2"
android:ems="10"
android:inputType="numberDecimal" />
<Button
android:id="@+id/button2"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_above="@+id/textView3"
android:layout_toRightOf="@+id/textView3"
android:text="-" />
<Button
android:id="@+id/button1"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignRight="@+id/textView3"
android:layout_centerVertical="true"
android:layout_marginRight="16dp"
android:text="+" />
<Button
android:id="@+id/button3"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView2"
android:layout_marginLeft="16dp"
android:layout_toRightOf="@+id/button2"
android:text="x" />
<Button
android:id="@+id/button4"
style="?android:attr/buttonStyleSmall"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@+id/textView2"
android:layout_marginLeft="16dp"
android:layout_toRightOf="@+id/button3"
android:text="÷" />
<EditText
android:id="@+id/editText3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignParentRight="true"
android:layout_alignTop="@+id/textView3"
android:ems="10"
android:inputType="numberDecimal" />
</RelativeLayout>
My Main.java：
import android.support.v7.app.ActionBarActivity;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
import android.content.Context;
import android.os.Bundle;
public class MainActivity extends ActionBarActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button plus = (Button)findViewById(R.id.button1);
Button minus = (Button)findViewById(R.id.button2);
Button multiply = (Button)findViewById(R.id.button3);
Button devide = (Button)findViewById(R.id.button4);
plus.setOnClickListener(Operation1);
minus.setOnClickListener(Operation1);
multiply.setOnClickListener(Operation1);
devide.setOnClickListener(Operation1);
}
///Your click listener method:
OnClickListener Operation1 = new OnClickListener() {
public void onClick(View v) {
final EditText editText1 = (EditText)findViewById(R.id.editText1);
final EditText editText2 = (EditText)findViewById(R.id.editText2);
final EditText editText3 = (EditText)findViewById(R.id.editText3);
if(editText1.getText().equals("") || editText2.getText().equals(""))
{
//toast the error message
Context context = getApplicationContext();
CharSequence text = "Please enter the numbers !";
int duration = Toast.LENGTH_SHORT;
Toast toast = Toast.makeText(context, text, duration);
toast.show();
return;
}
else
{
final double A = Double.valueOf(editText1.getText().toString());
final double B = Double.valueOf(editText2.getText().toString());
switch(v.getId()){
case R.id.button1:
double result = A+B;
editText3.setText(String.valueOf(result));
break;
case R.id.button2:
double result2 = A-B;
editText3.setText(String.valueOf(result2));
break;
case R.id.button3:
double result3 = A*B;
editText3.setText(String.valueOf(result3));
break;
case R.id.button4:
double result4 = A/B;
editText3.setText(String.valueOf(result4));
break;
}
}
}
};
}
和我的Logcat：
11-07 15:32:43.518: V/TLINE(364): new: android.text.TextLine@40685a60
11-07 15:32:43.877: V/TLINE(364): new: android.text.TextLine@406920b0
11-07 15:32:45.847: D/AndroidRuntime(364): Shutting down VM
11-07 15:32:45.847: W/dalvikvm(364): threadid=1: thread exiting with uncaught exception (group=0x40014760)
11-07 15:32:45.887: E/AndroidRuntime(364): FATAL EXCEPTION: main
11-07 15:32:45.887: E/AndroidRuntime(364): java.lang.NumberFormatException: Invalid double: ""
11-07 15:32:45.887: E/AndroidRuntime(364): at org.apache.harmony.luni.util.FloatingPointParser.invalidReal(FloatingPointParser.java:78)
11-07 15:32:45.887: E/AndroidRuntime(364): at org.apache.harmony.luni.util.FloatingPointParser.parseDouble(FloatingPointParser.java:276)
11-07 15:32:45.887: E/AndroidRuntime(364): at java.lang.Double.parseDouble(Double.java:317)
11-07 15:32:45.887: E/AndroidRuntime(364): at java.lang.Double.valueOf(Double.java:354)
11-07 15:32:45.887: E/AndroidRuntime(364): at com.rayana.calculator2.MainActivity$1.onClick(MainActivity.java:62)
11-07 15:32:45.887: E/AndroidRuntime(364): at android.view.View.performClick(View.java:3100)
11-07 15:32:45.887: E/AndroidRuntime(364): at android.view.View$PerformClick.run(View.java:11644)
11-07 15:32:45.887: E/AndroidRuntime(364): at android.os.Handler.handleCallback(Handler.java:587)
11-07 15:32:45.887: E/AndroidRuntime(364): at android.os.Handler.dispatchMessage(Handler.java:92)
11-07 15:32:45.887: E/AndroidRuntime(364): at android.os.Looper.loop(Looper.java:126)
11-07 15:32:45.887: E/AndroidRuntime(364): at android.app.ActivityThread.main(ActivityThread.java:3997)
11-07 15:32:45.887: E/AndroidRuntime(364): at java.lang.reflect.Method.invokeNative(Native Method)
11-07 15:32:45.887: E/AndroidRuntime(364): at java.lang.reflect.Method.invoke(Method.java:491)
11-07 15:32:45.887: E/AndroidRuntime(364): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:841)
11-07 15:32:45.887: E/AndroidRuntime(364): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:599)
11-07 15:32:45.887: E/AndroidRuntime(364): at dalvik.system.NativeStart.main(Native Method)
11-07 15:32:46.017: D/dalvikvm(364): GC_CONCURRENT freed 193K, 5% free 6460K/6791K, paused 4ms+12ms
答案 0 :(得分：1)
问题是editText1或editText2中的值不是有效的double值。
你应该围绕这些线：
final double A = Double.valueOf(editText1.getText().toString());
final double B = Double.valueOf(editText2.getText().toString());
使用try / catch块，例如：
try{
final double A = Double.valueOf(editText1.getText().toString());
final double B = Double.valueOf(editText2.getText().toString());
}catch(NumberFormatException e){
//invalid double value
}
答案 1 :(得分：1)
将您的代码更改为：
if(editText1.getText().toString().equals("") || editText2.getText().toString().equals(""))
我猜您忘记添加toString，因此equals方法会给出错误的结果，因此您的代码会转到else语句和{ {1}}发生在那里（因为“”不一个NumberFormatException）。
答案 2 :(得分：0)
您的错误发生在com.rayana.calculator2.MainActivity$1.onClick(MainActivity.java:62)
其中包含以下命令double result = A+B;
没有你要找的双打