相关疑难解决方法(0)

我正在尝试创建我的第一个自定义View子类GraphView并将其添加到我的布局XML文件中.

我发现了这个问题并试图将它应用到我的项目中,但似乎有些错误,因为Eclipse IDE告诉我:

de.muza3000.graph.GraphView failed to instantiate.

并抛出异常:

java.lang.NoSuchMethodException: de.muza3000.graph.GraphView.<init>(android.content.Context, android.util.AttributeSet)
at java.lang.Class.getConstructor0(Unknown Source)
at java.lang.Class.getConstructor(Unknown Source)
at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.instantiateClass(Unknown Source)
at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.loadView(Unknown Source)
at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:198)
at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:126)
at android.view.LayoutInflater.rInflate(LayoutInflater.java:618)
at android.view.LayoutInflater.inflate(LayoutInflater.java:407)
at android.view.LayoutInflater.inflate(LayoutInflater.java:296)
at com.android.layoutlib.bridge.Bridge.computeLayout(Bridge.java:396)
at com.android.ide.common.rendering.LayoutLibrary.createLegacySession(LayoutLibrary.java:382)
at com.android.ide.common.rendering.LayoutLibrary.createSession(LayoutLibrary.java:276)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(Unknown Source)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(Unknown Source)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.recomputeLayout(Unknown Source)
at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(Unknown Source)
at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditor.pageChange(Unknown Source)
at org.eclipse.ui.part.MultiPageEditorPart$2.widgetSelected(MultiPageEditorPart.java:290)
at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:234)
at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1053)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1077)
at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1062)
at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:774)
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) …

我想在android中的imageview上显示画布内容

我不理解imageview.draw(画布);

继承我的代码:

public class Matrix extends Activity {
    public Bitmap mybitmap,newbmp,bitmap,bmp;
    ImageView imageview;

    Paint paint;
    @Override
    public void onCreate(final Bundle savedInstanceState)
    {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        imageview=(ImageView)findViewById(R.id.ImageView01);
        imageview.setDrawingCacheEnabled(true);
    }

    protected void onDraw(Canvas canvas)
    {
        imageview.draw(canvas);
        mybitmap=BitmapFactory.decodeResource(getResources(), R.drawable.image);
        canvas.drawBitmap(mybitmap, 0, 0, paint);
    }

}