我试图从 radioButton 获取字符串值,但是当我尝试时,它在 LogCat 上显示此错误。我似乎不知道如何修复它..这些是代码:
protected void onCreate(Bundle konsumsi) {
super.onCreate(konsumsi);
radioAktivitasGroup = (RadioGroup) findViewById(R.id.radioAktivitasGroup);
setContentView(R.layout.aktivitas_user);
usernameP = Login.usernameP;
System.out.println(usernameP);
buttonDone();
}
public void buttonDone() {
selesai = (Button) findViewById(R.id.buttonProses);
selesai.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
int selectedId = radioAktivitasGroup.getCheckedRadioButtonId();
radioAktivitasButton = (RadioButton) findViewById(selectedId);
String Aktivitas = radioAktivitasButton.getText().toString();
}
});
}
错误:
05-20 07:01:07.858: E/AndroidRuntime(3179): java.lang.RuntimeException: Unable to start activity ComponentInfo{com.ta.nutrifact/com.ta.nutrifact.AktivitasUser}: java.lang.NullPointerException
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2211)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2261)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.ActivityThread.access$600(ActivityThread.java:141)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.ActivityThread$H.handleMessage(ActivityThread.java:1256)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.os.Handler.dispatchMessage(Handler.java:99)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.os.Looper.loop(Looper.java:137)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.ActivityThread.main(ActivityThread.java:5103)
05-20 07:01:07.858: E/AndroidRuntime(3179): at java.lang.reflect.Method.invokeNative(Native Method)
05-20 07:01:07.858: E/AndroidRuntime(3179): at java.lang.reflect.Method.invoke(Method.java:525)
05-20 07:01:07.858: E/AndroidRuntime(3179): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:737)
05-20 07:01:07.858: E/AndroidRuntime(3179): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
05-20 07:01:07.858: E/AndroidRuntime(3179): at dalvik.system.NativeStart.main(Native Method)
05-20 07:01:07.858: E/AndroidRuntime(3179): Caused by: java.lang.NullPointerException
05-20 07:01:07.858: E/AndroidRuntime(3179): at com.ta.nutrifact.AktivitasUser.onCreate(AktivitasUser.java:71)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.Activity.performCreate(Activity.java:5133)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.Instrumentation.callActivityOnCreate(Instrumentation.java:1087)
05-20 07:01:07.858: E/AndroidRuntime(3179): at android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2175)
05-20 07:01:07.858: E/AndroidRuntime(3179): ... 11 more
我在另一门课上做了完全相同的事情,它有效,但在这门课上不起作用。任何帮助,将不胜感激。谢谢
最佳答案
颠倒陈述
radioAktivitasGroup = (RadioGroup) findViewById(R.id.radioAktivitasGroup);
setContentView(R.layout.aktivitas_user);
至
setContentView(R.layout.aktivitas_user);
radioAktivitasGroup = (RadioGroup) findViewById(R.id.radioAktivitasGroup);
关于尝试从 radioButton 获取值时出现 java.lang.NullPointerException (Android),我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/23758192/