我一直在用手机调试我的应用程序,我得到的所有 logcat 错误都引用我的 Activity 中的第 54 行,其中我将 String 解析为 Int。该应用程序的基本思想是一个便士转换器,用户可以在其中输入他们想要转换的便士数量,然后将其从四分之一到剩余的便士进行划分。此时,我不确定我是否正确捕获了该事件,并反复使用匿名内部类并在类中实现。
这是 Java 应用程序的代码:
public class PennyConverterActivity extends Activity
{
EditText et;
TextView tv;
int cents;
int remaining;
int quarters;
int dimes;
int nickels;
int pennies;
String result;
@Override
public void onCreate(Bundle b)
{
super.onCreate(b);
setContentView(R.layout.main);
et = (EditText) findViewById(R.id.penny);
et.setText(result);
et.setOnKeyListener(new View.OnKeyListener()
{
@Override
public boolean onKey(View v, int keyCode, KeyEvent event)
{
if((event.getAction() == KeyEvent.ACTION_DOWN) && (keyCode == KeyEvent.KEYCODE_ENTER))
{
result = et.getText().toString();
return (true);
}
return (true);
}
});
cents = Integer.parseInt(result); //LogCat error refers to this line
tv = (TextView) findViewById(R.id.quarters);
quarters = cents / 25;
tv.setText(R.string.quarters);
remaining = cents % 25;
tv = (TextView) findViewById(R.id.dimes);
dimes = remaining / 10;
tv.setText(R.string.dimes);
remaining = remaining % 10;
tv = (TextView) findViewById(R.id.nickels);
nickels = remaining / 5;
tv.setText(R.string.nickles);
tv = (TextView) findViewById(R.id.pennies);
pennies = remaining % 5;
tv.setText(R.string.pennies);
}
}
和我的 Logcat 错误
02-26 15:26:30.602: E/AndroidRuntime(25020): FATAL EXCEPTION: main
02-26 15:26:30.602: E/AndroidRuntime(25020): java.lang.RuntimeException: Unable to start activity ComponentInfo{CS211D.HW03.PennyConverter/CS211D.HW03.PennyConverter.PennyConverterActivity}: java.lang.NumberFormatException: unable to parse 'null' as integer
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1647)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:1663)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.app.ActivityThread.access$1500(ActivityThread.java:117)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:931)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.os.Handler.dispatchMessage(Handler.java:99)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.os.Looper.loop(Looper.java:130)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.app.ActivityThread.main(ActivityThread.java:3683)
02-26 15:26:30.602: E/AndroidRuntime(25020): at java.lang.reflect.Method.invokeNative(Native Method)
02-26 15:26:30.602: E/AndroidRuntime(25020): at java.lang.reflect.Method.invoke(Method.java:507)
02-26 15:26:30.602: E/AndroidRuntime(25020): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-26 15:26:30.602: E/AndroidRuntime(25020): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-26 15:26:30.602: E/AndroidRuntime(25020): at dalvik.system.NativeStart.main(Native Method)
02-26 15:26:30.602: E/AndroidRuntime(25020): Caused by: java.lang.NumberFormatException: unable to parse 'null' as integer
02-26 15:26:30.602: E/AndroidRuntime(25020): at java.lang.Integer.parseInt(Integer.java:356)
02-26 15:26:30.602: E/AndroidRuntime(25020): at java.lang.Integer.parseInt(Integer.java:332)
02-26 15:26:30.602: E/AndroidRuntime(25020): at CS211D.HW03.PennyConverter.PennyConverterActivity.onCreate(PennyConverterActivity.java:52)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1047)
02-26 15:26:30.602: E/AndroidRuntime(25020): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:1611)
02-26 15:26:30.602: E/AndroidRuntime(25020): ... 11 more
最佳答案
问题是您没有初始化结果
并且当您调用 Integer.parseInt(result)
时,它无法解析 null
。从您得到的异常中可以明显看出这一点:
Caused by: java.lang.NumberFormatException: unable to parse 'null' as integer
关于java - Android 应用程序在第 54 行(Integer.parseInt)处崩溃,并且不完全确定原因,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/9458635/