私は、TestApp
which extendsという名前のクラスActivity
と、whichextendsという名前の別のクラスを持ってSecondClass
いますTestApp
。TestApp
アクティビティには、ボタンにテキストを設定するメソッドがあります。ボタンのオブジェクトに移動しTestApp
てからSecondClass
のメソッドを呼び出すとき。なぜこうなった ?どんな提案も認められるでしょう。これが私の最初のアクティビティコードです。TestApp
SecondClass
NullPointerException
@Override
public void onCreate(Bundle savedInstanceState) {
ok = (Button) findViewById(R.id.button1);
cancel = (Button) findViewById(R.id.button2);
setTextAgain();
}
protected void setTextAgain() {
ok.setText("hi");
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
menu.add(0, 0, 1, "1");
return super.onCreateOptionsMenu(menu);
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
switch (item.getItemId()) {
case 0:
SecondClass second = new SecondClass(this);
second.initialize();
break;
}
return super.onOptionsItemSelected(item);
}
これが私のセカンドクラスコードです
public class SecondClass extends TestAppActivity{
Context l_context;
public SecondClass(TestAppActivity p_testAppActivity) {
l_context = p_testAppActivity;
}
public void initialize() {
setTextAgain();
}
これはlogCato/pです
02-17 22:43:54.159: E/AndroidRuntime(1246): java.lang.NullPointerException
02-17 22:43:54.159: E/AndroidRuntime(1246): at
android.app.Activity.setContentView(Activity.java:1657)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.sachit.testApp.TestAppActivity.setTextAgain(TestAppActivity.java:25)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.sachit.testApp.SecondClass.initialize(SecondClass.java:17)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.sachit.testApp.TestAppActivity.onOptionsItemSelected(TestAppActivity.java:46)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
android.app.Activity.onMenuItemSelected(Activity.java:2205)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.android.internal.policy.impl.PhoneWindow.onMenuItemSelected(PhoneWindow.java:748)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.android.internal.view.menu.MenuItemImpl.invoke(MenuItemImpl.java:143)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.android.internal.view.menu.MenuBuilder.performItemAction(MenuBuilder.java:855)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.android.internal.view.menu.IconMenuView.invokeItem(IconMenuView.java:532)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.android.internal.view.menu.IconMenuItemView.performClick(IconMenuItemView.java:122)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
android.view.View$PerformClick.run(View.java:9080)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
android.os.Handler.handleCallback(Handler.java:587)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
android.os.Handler.dispatchMessage(Handler.java:92)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
android.os.Looper.loop(Looper.java:123)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
android.app.ActivityThread.main(ActivityThread.java:3683)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
java.lang.reflect.Method.invokeNative(Native Method)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
java.lang.reflect.Method.invoke(Method.java:507)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:839)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
com.android.internal.os.ZygoteInit.main(ZygoteInit.java:597)
02-17 22:43:54.159: E/AndroidRuntime(1246): at
dalvik.system.NativeStart.main(Native Method)