当我使用简单的TextView从一个Activity重定位到另一个Activity时 - 它可以工作 . 一段代码:
private RMProject currentProject;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.open_proj);
Bundle bundle = getIntent().getExtras();
currentProject = bundle.getParcelable("current");
TextView textView = (TextView) findViewById(R.id.label_open_project);
textView.setText("Project "+currentProject.getName());
}
但是当我在 onCreate() 方法中使用下一个代码的另一个活动时 - 它不起作用,我收到NullPointerException . 在第38行 . 我检查过,我在使用第一段代码时收到了textView .
public class EventsActivity extends Activity {
private RMProject currentProject;
private ListView listView;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
EventDBManager.init(this);
ViewGroup contentView = (ViewGroup) getLayoutInflater().inflate(R.layout.orm_event_list, null);
listView = (ListView) contentView.findViewById(R.id.ormListView);
Bundle bundle = getIntent().getExtras();
currentProject = bundle.getParcelable("current");
TextView textView = (TextView) findViewById(R.id.ormTextView);
//38 line - next, which cause exception
textView.setText("Project "+currentProject.getName());
Button btn = (Button) contentView.findViewById(R.id.ormButtonAdd);
setupButton(btn);
setContentView(contentView);
}
}
我猜这个问题与组件布局有关 . 这是我的布局文件:
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:editable="true"
android:text="Project name"
android:id="@+id/ormTextView"
android:layout_alignParentTop="true"
android:layout_alignParentStart="true"
android:layout_marginLeft="90dp"
android:textSize="20dp"/>
<Button
android:id="@+id/ormButtonAdd"
android:layout_alignParentBottom="true"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:text="Add " />
<ListView
android:id="@+id/ormListView"
android:layout_above="@id/ormButtonAdd"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</RelativeLayout>
我被收到的例外:
04-15 18:26:29.209 1401-1401 / nikolay.rm E / AndroidRuntime:FATAL EXCEPTION:main进程:nikolay.rm,PID:1401 java.lang.RuntimeException:无法启动活动ComponentInfo {nikolay.rm / nikolay .rm.activities.EventsActivity}:android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2195)中的android.app.A活动时,我发现它是android.app.A活动中的android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)的java.lang.NullPointerException . 在Android.os.Looper.loop上的android.app.Handler.dispatchMessage(Handler.java:102)的android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1196)访问$ 800(ActivityThread.java:135)( Looper.java:136)在java.lang.reflect.Method.invoke的java.lang.reflect.Method.invokeNative(Native Method)的android.app.ActivityThread.main(ActivityThread.java:5017)上(Method.java: 515)在com.android.internal.os.ZygoteInit $ MethodAndArgsCaller.run(ZygoteInit.java:779)位于dalvik.system.NativeStart的com.android.internal.os.ZygoteInit.main(ZygoteInit.java:595) . main(Native方法)由android.app的android.app.Activity.performCreate(Activity.java:5231)上的nikolay.rm.activities.EventsActivity.onCreate(EventsActivity.java:38)引起的java.lang.NullPointerException . Instrumentation.callActivityOnCreate(Instrumentation.java:1087)在android.app.ActivityThread.performLaunchActivity(ActivityThread.java:2159)的android.app.ActivityThread.handleLaunchActivity(ActivityThread.java:2245)android.app.ActivityThread.access $ 800( ActivityThread.java:135)在Android.os.Looper.loop(Looper.java)android.app.Handler.dispatchMessage(Handler.java:102)的android.app.ActivityThread $ H.handleMessage(ActivityThread.java:1196) :136)在java.lang.reflect.Method.invoke的java.lang.reflect.Method.invokeNative(Native Method)的android.app.ActivityThread.main(ActivityThread.java:5017)(Method.java:515)
1 回答
您在以下行中缺少contentView参考
所以修复就是替换它
希望这可以帮助