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我有一個自定義視圖，我必須將它放在一個線性佈局中，並將layout_gravity = center。 這是自定義視圖：自定義視圖不以xml佈局爲中心android
public class GIFView extends View{
private Movie movie;
private InputStream is;
private long moviestart;
public GIFView(Context context) {
super(context);
is=context.getResources().openRawResource(R.drawable.anim_cerca);
movie=Movie.decodeStream(is);
}
public GIFView(Context context, AttributeSet attrs)
{
super(context, attrs);
is=context.getResources().openRawResource(R.drawable.anim_cerca);
movie=Movie.decodeStream(is);
}
public GIFView(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
is=context.getResources().openRawResource(R.drawable.anim_cerca);
movie=Movie.decodeStream(is);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
long now=android.os.SystemClock.uptimeMillis();
Paint p = new Paint();
p.setAntiAlias(true);
if (moviestart == 0)
moviestart = now;
int relTime = (int)((now - moviestart) % movie.duration());
movie.setTime(relTime);
movie.draw(canvas,0,0);
this.invalidate();
}
}
這是我的xml：
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical" android:layout_width="match_parent"
android:layout_height="match_parent" android:background="@drawable/sfondo">
<LinearLayout android:id="@+id/linearLayout2"
android:layout_height="wrap_content" android:layout_width="match_parent"
android:orientation="vertical">
<LinearLayout android:id="@+id/linearLayout1"
android:layout_height="fill_parent" android:weightSum="1"
android:layout_width="fill_parent" android:orientation="horizontal">
<ImageView android:layout_height="wrap_content" android:id="@+id/imageView1"
android:src="@drawable/trovachiavi" android:layout_width="wrap_content"
android:layout_marginTop="10dp" android:layout_marginLeft="5dp"></ImageView>
<ImageButton android:id="@+id/infoButton"
android:background="@null" android:layout_height="47dp"
android:layout_marginLeft="5dip" android:layout_weight="0.25"
android:layout_marginTop="15dip" android:src="@drawable/info_mini"
android:layout_width="47dp">
</ImageButton>
</LinearLayout>
</LinearLayout>
<ImageButton android:id="@+id/avvia_cerca"
android:background="@null" android:layout_gravity="center|bottom"
android:layout_height="wrap_content" android:layout_width="wrap_content"
android:layout_marginTop="10dp"></ImageButton>
<LinearLayout android:id="@+id/layoutGIF"
android:layout_height="wrap_content" android:layout_width="wrap_content"
android:orientation="vertical">
<spazio.digitale.com.GIFView android:id="@+id/gIFView1"
android:layout_width="wrap_content" android:layout_height="wrap_content"
android:layout_gravity="center"></spazio.digitale.com.GIFView>
</LinearLayout>
</LinearLayout>
當我在Eclipse開放的圖形化工具來設計XML，它給我這個錯誤：
java.lang.NullPointerException
at spazio.digitale.com.GIFView.onDraw(GIFView.java:43)
at android.view.View.draw(View.java:6880)
at android.view.ViewGroup.drawChild(ViewGroup.java:1646)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.ViewGroup.drawChild(ViewGroup.java:1644)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.View.draw(View.java:6883)
at android.view.ViewGroup.drawChild(ViewGroup.java:1646)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.ViewGroup.drawChild(ViewGroup.java:1644)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.View.draw(View.java:6883)
at android.view.ViewGroup.drawChild(ViewGroup.java:1646)
at android.view.ViewGroup.dispatchDraw(ViewGroup.java:1373)
at android.view.View.draw(View.java:6883)
at com.android.layoutlib.bridge.impl.RenderSessionImpl.render(RenderSessionImpl.java:466)
at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:320)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:325)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.RenderService.createRenderSession(RenderService.java:380)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(GraphicalEditorPart.java:1310)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.recomputeLayout(GraphicalEditorPart.java:1075)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(GraphicalEditorPart.java:901)
at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditor.partActivated(LayoutEditor.java:416)
at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditor.partBroughtToTop(LayoutEditor.java:425)
at org.eclipse.ui.internal.PartListenerList$2.run(PartListenerList.java:87)
at org.eclipse.core.runtime.SafeRunner.run(SafeRunner.java:42)
at org.eclipse.core.runtime.Platform.run(Platform.java:888)
at org.eclipse.ui.internal.PartListenerList.fireEvent(PartListenerList.java:57)
at org.eclipse.ui.internal.PartListenerList.firePartBroughtToTop(PartListenerList.java:85)
at org.eclipse.ui.internal.PartService.firePartBroughtToTop(PartService.java:208)
at org.eclipse.ui.internal.WorkbenchPagePartList.firePartBroughtToTop(WorkbenchPagePartList.java:76)
at org.eclipse.ui.internal.WorkbenchPagePartList.fireActiveEditorChanged(WorkbenchPagePartList.java:52)
at org.eclipse.ui.internal.PartList.setActiveEditor(PartList.java:162)
at org.eclipse.ui.internal.WorkbenchPage.makeActiveEditor(WorkbenchPage.java:1281)
at org.eclipse.ui.internal.WorkbenchPage.setActivePart(WorkbenchPage.java:3530)
at org.eclipse.ui.internal.WorkbenchPage.requestActivation(WorkbenchPage.java:3077)
at org.eclipse.ui.internal.PartPane.requestActivation(PartPane.java:279)
at org.eclipse.ui.internal.EditorPane.requestActivation(EditorPane.java:98)
at org.eclipse.ui.internal.PartPane.setFocus(PartPane.java:325)
at org.eclipse.ui.internal.EditorPane.setFocus(EditorPane.java:127)
at org.eclipse.ui.internal.PartStack.presentationSelectionChanged(PartStack.java:844)
at org.eclipse.ui.internal.PartStack.access$1(PartStack.java:827)
at org.eclipse.ui.internal.PartStack$1.selectPart(PartStack.java:137)
at org.eclipse.ui.internal.presentations.util.TabbedStackPresentation$1.handleEvent(TabbedStackPresentation.java:133)
at org.eclipse.ui.internal.presentations.util.AbstractTabFolder.fireEvent(AbstractTabFolder.java:269)
at org.eclipse.ui.internal.presentations.util.AbstractTabFolder.fireEvent(AbstractTabFolder.java:278)
at org.eclipse.ui.internal.presentations.defaultpresentation.DefaultTabFolder.access$1(DefaultTabFolder.java:1)
at org.eclipse.ui.internal.presentations.defaultpresentation.DefaultTabFolder$2.handleEvent(DefaultTabFolder.java:88)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:3783)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1375)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1398)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1383)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1195)
at org.eclipse.swt.custom.CTabFolder.setSelection(CTabFolder.java:2743)
at org.eclipse.swt.custom.CTabFolder.onMouse(CTabFolder.java:1429)
at org.eclipse.swt.custom.CTabFolder$1.handleEvent(CTabFolder.java:257)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Display.sendEvent(Display.java:3783)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1375)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1398)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1383)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1195)
at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3629)
at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3284)
at org.eclipse.ui.internal.Workbench.runEventLoop(Workbench.java:2640)
at org.eclipse.ui.internal.Workbench.runUI(Workbench.java:2604)
at org.eclipse.ui.internal.Workbench.access$4(Workbench.java:2438)
at org.eclipse.ui.internal.Workbench$7.run(Workbench.java:671)
at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332)
at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:664)
at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149)
at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:115)
at org.eclipse.equinox.internal.app.EclipseAppHandle.run(EclipseAppHandle.java:196)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.runApplication(EclipseAppLauncher.java:110)
at org.eclipse.core.runtime.internal.adaptor.EclipseAppLauncher.start(EclipseAppLauncher.java:79)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:369)
at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:179)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:620)
at org.eclipse.equinox.launcher.Main.basicRun(Main.java:575)
at org.eclipse.equinox.launcher.Main.run(Main.java:1408)
如果我把自定義視圖放在其他元素的上面，在設備上運行它，這些元素將不會顯示。當xml在這裏完成時，我將所有其他元素放在自定義視圖上方，以便它們顯示，但自定義視圖不在佈局中居中。我能做什麼？