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POAndroid: Custom view 'PointsView': Error "The following classes could not be instantiated"
 

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  1. POAndroid: Custom view 'PointsView': Error "The following classes could not be instantiated"
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    <p>I'm creating an Android Yahtzee game app. To keep track of player scores, I've tried to create a PointsView class to hold these scores. However, I'm getting a "The following classes could not be instantiated: - uk.ac.surrey.jb00359.yatzy.PointsView... See Error Log (Window > Show View)..." error for PointsView when I try to create it within my game XML layout file, shown below.</p> <pre><code>&lt;?xml version="1.0" encoding="utf-8"?&gt; &lt;RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="fill_parent" android:layout_height="fill_parent" android:background="@color/background_colour" &gt; &lt;Button android:id="@+id/roll_button" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:layout_marginBottom="@dimen/die_margin" android:layout_marginLeft="@dimen/die_margin" android:text="@string/roll_button_text" /&gt; &lt;TextView android:id="@+id/player_turn" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@id/roll_button" android:layout_alignParentRight="true" android:layout_marginRight="@dimen/die_margin" android:text="@string/player_1_turn_text" android:textSize="18sp" /&gt; &lt;ImageView android:id="@+id/die_3" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_above="@id/roll_button" android:layout_marginBottom="@dimen/die_margin" android:layout_centerHorizontal="true" android:contentDescription="@string/die_3_description" android:src="@drawable/dice_1" /&gt; &lt;ImageView android:id="@+id/die_2" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@id/die_3" android:layout_toLeftOf="@id/die_3" android:layout_marginRight="@dimen/die_margin" android:contentDescription="@string/die_2_description" android:src="@drawable/dice_1" /&gt; &lt;ImageView android:id="@+id/die_1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@id/die_2" android:layout_toLeftOf="@id/die_2" android:layout_marginRight="@dimen/die_margin" android:contentDescription="@string/die_1_description" android:src="@drawable/dice_1" /&gt; &lt;ImageView android:id="@+id/die_4" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@id/die_3" android:layout_toRightOf="@id/die_3" android:layout_marginLeft="@dimen/die_margin" android:contentDescription="@string/die_4_description" android:src="@drawable/dice_1" /&gt; &lt;ImageView android:id="@+id/die_5" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignBottom="@id/die_4" android:layout_toRightOf="@id/die_4" android:layout_marginLeft="@dimen/die_margin" android:contentDescription="@string/die_5_description" android:src="@drawable/dice_1" /&gt; &lt;uk.ac.surrey.jb00359.yatzy.PointsView android:id="@+id/points_view" android:layout_width="match_parent" android:layout_height="match_parent" android:layout_marginLeft="@dimen/points_view_margin" android:layout_marginTop="@dimen/points_view_margin" android:layout_marginRight="@dimen/points_view_margin" android:layout_marginBottom="@dimen/die_margin" android:layout_above="@id/die_1" /&gt; &lt;/RelativeLayout&gt; </code></pre> <p>When I look up the error log, it gives me this exception stack trace:</p> <pre><code>java.lang.NoSuchMethodException: uk.ac.surrey.jb00359.yatzy.PointsView.&lt;init&gt;(android.content.Context, android.util.AttributeSet) at java.lang.Class.getConstructor0(Class.java:2733) at java.lang.Class.getConstructor(Class.java:1676) at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.instantiateClass(ProjectCallback.java:347) at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.loadView(ProjectCallback.java:179) at android.view.BridgeInflater.loadCustomView(BridgeInflater.java:207) at android.view.BridgeInflater.createViewFromTag(BridgeInflater.java:135) at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:746) at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:64) at android.view.LayoutInflater.rInflate(LayoutInflater.java:718) at android.view.LayoutInflater.inflate(LayoutInflater.java:489) at android.view.LayoutInflater.inflate(LayoutInflater.java:372) at com.android.layoutlib.bridge.impl.RenderSessionImpl.inflate(RenderSessionImpl.java:385) at com.android.layoutlib.bridge.Bridge.createSession(Bridge.java:332) 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:440) at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.renderWithBridge(GraphicalEditorPart.java:1545) at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.recomputeLayout(GraphicalEditorPart.java:1302) at com.android.ide.eclipse.adt.internal.editors.layout.gle2.GraphicalEditorPart.activated(GraphicalEditorPart.java:1059) at com.android.ide.eclipse.adt.internal.editors.layout.LayoutEditorDelegate.delegatePageChange(LayoutEditorDelegate.java:686) at com.android.ide.eclipse.adt.internal.editors.common.CommonXmlEditor.pageChange(CommonXmlEditor.java:360) at org.eclipse.ui.part.MultiPageEditorPart$2.widgetSelected(MultiPageEditorPart.java:292) at org.eclipse.swt.widgets.TypedListener.handleEvent(TypedListener.java:248) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1276) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1300) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1285) at org.eclipse.swt.widgets.Widget.notifyListeners(Widget.java:1079) at org.eclipse.swt.custom.CTabFolder.setSelection(CTabFolder.java:3023) at org.eclipse.swt.custom.CTabFolder.onMouse(CTabFolder.java:1730) at org.eclipse.swt.custom.CTabFolder$1.handleEvent(CTabFolder.java:270) at org.eclipse.swt.widgets.EventTable.sendEvent(EventTable.java:84) at org.eclipse.swt.widgets.Widget.sendEvent(Widget.java:1276) at org.eclipse.swt.widgets.Display.runDeferredEvents(Display.java:3554) at org.eclipse.swt.widgets.Display.readAndDispatch(Display.java:3179) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine$9.run(PartRenderingEngine.java:1022) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.e4.ui.internal.workbench.swt.PartRenderingEngine.run(PartRenderingEngine.java:916) at org.eclipse.e4.ui.internal.workbench.E4Workbench.createAndRunUI(E4Workbench.java:86) at org.eclipse.ui.internal.Workbench$5.run(Workbench.java:585) at org.eclipse.core.databinding.observable.Realm.runWithDefault(Realm.java:332) at org.eclipse.ui.internal.Workbench.createAndRunWorkbench(Workbench.java:540) at org.eclipse.ui.PlatformUI.createAndRunWorkbench(PlatformUI.java:149) at org.eclipse.ui.internal.ide.application.IDEApplication.start(IDEApplication.java:124) 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:353) at org.eclipse.core.runtime.adaptor.EclipseStarter.run(EclipseStarter.java:180) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:616) at org.eclipse.equinox.launcher.Main.invokeFramework(Main.java:629) at org.eclipse.equinox.launcher.Main.basicRun(Main.java:584) at org.eclipse.equinox.launcher.Main.run(Main.java:1438) at org.eclipse.equinox.launcher.Main.main(Main.java:1414) </code></pre> <p>So far, I have tried overriding my PointView's onMeasure() method using code kindly provided by stackoverflow user Devunwired at "<a href="https://stackoverflow.com/questions/12266899/onmeasure-custom-view-explanation">onMeasure custom view explanation</a>", but so far with no noticeable success. (See below)</p> <pre><code>package uk.ac.surrey.jb00359.yatzy; import android.content.Context; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Paint.Style; import android.util.AttributeSet; import android.view.View; /** * * This class outputs the current scores obtained by the two Yatzy players */ public class PointsView extends View { // Do not change these values! private static final float noOfColumns = 3f; private static final float noOfRows = 19f; private GameActivity game; private GameLogic gameLogic; private Paint majorLinePaint = new Paint(); private Paint minorLinePaint = new Paint(); /** * Colour of score cells, that can be selected to store * a player's new dice score after a round (1-3 dice throws) */ private Paint selectablePaint = new Paint(); private Paint textPaint = new Paint(Paint.ANTI_ALIAS_FLAG); private float top, left, bottom, right; // grid boundaries private float cellWidth, cellHeight; // Cell sizes public PointsView(Context context, AttributeSet attrs, GameLogic gameLogic) { super(context, attrs); // Allow the view to refer to the game activity and game logic (state) this.game = (GameActivity) context; this.gameLogic = gameLogic; majorLinePaint.setColor(getResources().getColor(R.color.major_line_colour)); minorLinePaint.setColor(getResources().getColor(R.color.minor_line_colour)); selectablePaint.setColor(getResources().getColor(R.color.selectable_cell_colour)); textPaint.setColor(getResources().getColor(R.color.text_colour)); textPaint.setStyle(Style.FILL); textPaint.setTextScaleX(1f); textPaint.setTextAlign(Paint.Align.CENTER); } @Override protected void onSizeChanged(int w, int h, int oldw, int oldh) { top = 0; left = 0; bottom = h; right = w; cellWidth = w / noOfColumns; // 3 columns of cells cellHeight = h / noOfRows; // 19 rows of cells // Set text size to be 7/8 of the height of each cell textPaint.setTextSize(cellHeight * (7/8)); super.onSizeChanged(w, h, oldw, oldh); } @Override protected void onDraw(Canvas canvas) { // Draw the PointsView's grid lines for (int i = 0; i &lt;= noOfColumns; i++) { // Draw column lines canvas.drawLine(left + i*cellWidth, top, left + i*cellWidth, bottom, majorLinePaint); } for (int j = 0; j &lt;= noOfRows; j++) { // Draw row lines canvas.drawLine(left, top + j*cellHeight, right, top + j*cellHeight, majorLinePaint); } // More drawing later... } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { /** * Here starts Devunwired's code from * https://stackoverflow.com/questions/12266899/onmeasure-custom-view-explanation */ int desiredWidth = 100; int desiredHeight = 100; int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int width; int height; //Measure Width if (widthMode == MeasureSpec.EXACTLY) { //Must be this size width = widthSize; } else if (widthMode == MeasureSpec.AT_MOST) { //Can't be bigger than... width = Math.min(desiredWidth, widthSize); } else { //Be whatever you want width = desiredWidth; } //Measure Height if (heightMode == MeasureSpec.EXACTLY) { //Must be this size height = heightSize; } else if (heightMode == MeasureSpec.AT_MOST) { //Can't be bigger than... height = Math.min(desiredHeight, heightSize); } else { //Be whatever you want height = desiredHeight; } //MUST CALL THIS setMeasuredDimension(width, height); /** End of Devunwired's code */ } } </code></pre> <p>Would anyone know what's happening in my code to cause this error?</p>
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