Cómo usar isInEditMode () para ver el diseño con vista personalizada en el editor

Debo editar un software que tenga una vista personalizada, cuando trato de editar el diseño xml, Eclipse me dice:

Use View.isInEditMode () en sus vistas personalizadas para omitir el código cuando se muestra en Eclipse

Pero no tengo idea de cómo y dónde debo usar isInEditMode () en la aplicación

Mi archivo xml es

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 
     xmlns:android="http://schemas.android.com/apk/res/android"
     android:orientation="vertical"
     android:layout_width="fill_parent"
     android:layout_height="fill_parent"
     android:background="#ff000000"
    >
<TextView
     android:id="@+id/result"
     android:layout_width="fill_parent" 
     android:layout_height="wrap_content"
     android:gravity="right"
     android:textSize="32dip"
     android:scrollbars="none"
     android:lines="1"
     android:freezesText="true"
     android:textColor="@color/result"
    />
<EditText
     android:id="@+id/input"
     android:layout_width="fill_parent"
     android:layout_height="wrap_content"
     android:gravity="left"
     android:textSize="28dip"
     android:scrollbars="none"
     android:singleLine="true"
     android:autoText="false"
     android:imeOptions="flagNoEnterAction|flagNoExtractUi"
     />
<ListView
     android:id="@+id/history"
     android:layout_width="fill_parent"
     android:layout_height="0dip"
     android:layout_weight="1"
     android:cacheColorHint="#ff000000"
     android:choiceMode="singleChoice"
     android:scrollbarStyle="outsideInset"
     android:scrollbars="none"
    />
<calculator.GraphView
     android:id="@+id/graph"
     android:layout_width="fill_parent"
     android:layout_height="0dip"
     android:layout_weight="1"
     android:visibility="gone"
     />
<include layout="@layout/keyboard" />
</LinearLayout>

Y mi GraphView es

public class GraphView extends View implements Grapher,
        ZoomButtonsController.OnZoomListener,
        TouchHandler.TouchHandlerInterface {
    private int width, height;
    private Matrix matrix = new Matrix();
    private Paint paint = new Paint();
    private Paint textPaint = new Paint();
    private ArrayList<Function> funcs = new ArrayList<Function>();
    private Data next = new Data(), endGraph = new Data();
    private Data graphs[] = { new Data(), new Data(), new Data(), new Data(),
            new Data() };
    private static final int GRAPHS_SIZE = 5;
    private float gwidth = 8;
    private float currentX, currentY;
    private float lastMinX;
    private Scroller scroller;
    private float boundMinY, boundMaxY;
    protected ZoomButtonsController zoomController = new ZoomButtonsController(
            this);
    private ZoomTracker zoomTracker = new ZoomTracker();
    private TouchHandler touchHandler;
    private float lastTouchX, lastTouchY;

    private static final int COL_AXIS = 0xff00a000, COL_GRID = 0xff004000,
            COL_TEXT = 0xff00ff00;

    private static final int COL_GRAPH[] = { 0xffffffff, 0xff00ffff,
            0xffffff00, 0xffff00ff, 0xff80ff80 };

    public GraphView(Context context, AttributeSet attrs) {
        super(context, attrs);
        init(context);
    }

    public GraphView(Context context) {
        super(context);
        touchHandler = new TouchHandler(this);
        init(context);
    }

    private void init(Context context) {
        zoomController.setOnZoomListener(this);
        scroller = new Scroller(context);
        paint.setAntiAlias(false);
        textPaint.setAntiAlias(true);
    }

    @SuppressLint("WrongCall")
    public String captureScreenshot() {
        Bitmap bitmap = Bitmap.createBitmap(width, height,
                Bitmap.Config.RGB_565);
        Canvas canvas = new Canvas(bitmap);
        onDraw(canvas);
        return Util.saveBitmap(bitmap, Grapher.SCREENSHOT_DIR, "calculator");
    }

    private void clearAllGraph() {
        for (int i = 0; i < GRAPHS_SIZE; ++i) {
            graphs[i].clear();
        }
    }

    public void setFunctions(ArrayList<Function> fs) {
        funcs.clear();
        for (Function f : fs) {
            int arity = f.arity();
            if (arity == 0 || arity == 1) {
                funcs.add(f);
            }
        }
        clearAllGraph();
        invalidate();
    }

    public void setFunction(Function f) {
        funcs.clear();
        if (f != null) {
            funcs.add(f);
        }
        clearAllGraph();
        invalidate();
    }

    public void onVisibilityChanged(boolean visible) {
    }

    public void onZoom(boolean zoomIn) {
        if (zoomIn) {
            if (canZoomIn()) {
                gwidth /= 2;
                invalidateGraphs();
            }
        } else {
            if (canZoomOut()) {
                gwidth *= 2;
                invalidateGraphs();
            }
        }
        zoomController.setZoomInEnabled(canZoomIn());
        zoomController.setZoomOutEnabled(canZoomOut());
    }

    public void onResume() {
    }

    public void onPause() {
    }

    public void onDetachedFromWindow() {
        zoomController.setVisible(false);
        super.onDetachedFromWindow();
    }

    protected void onSizeChanged(int w, int h, int ow, int oh) {
        width = w;
        height = h;
        clearAllGraph();
    }

    protected void onDraw(Canvas canvas) {
        if (funcs.size() == 0) {
            return;
        }
        if (scroller.computeScrollOffset()) {
            final float scale = gwidth / width;
            currentX = scroller.getCurrX() * scale;
            currentY = scroller.getCurrY() * scale;
            if (!scroller.isFinished()) {
                invalidate();
            }
        }
        drawGraph(canvas);
    }

    private float eval(Function f, float x) {
        float v = (float) f.eval(x);

        if (v < -10000f) {
            return -10000f;
        }
        if (v > 10000f) {
            return 10000f;
        }
        return v;
    }

    private float distance2(float x1, float y1, float x2, float y2, float y) {
        final float dx = x2 - x1;
        final float dy = y2 - y1;
        final float up = dx * (y1 + y2 - y - y);
        return up * up / (dx * dx + dy * dy);
    }

    private void computeGraph(Function f, float minX, float maxX, float minY,
            float maxY, Data graph) {
        if (f.arity() == 0) {
            float v = (float) f.eval();
            if (v < -10000f) {
                v = -10000f;
            }
            if (v > 10000f) {
                v = 10000f;
            }
            graph.clear();
            graph.push(minX, v);
            graph.push(maxX, v);
            return;
        }

        final float scale = width / gwidth;
        final float maxStep = 15.8976f / scale;
        final float minStep = .05f / scale;
        float ythresh = 1 / scale;
        ythresh = ythresh * ythresh;
        if (!graph.empty()) {
            if (minX >= lastMinX) {
                graph.eraseBefore(minX);
            } else {
                graph.eraseAfter(maxX);
                maxX = Math.min(maxX, graph.firstX());
                graph.swap(endGraph);
            }
        }
        if (graph.empty()) {
            graph.push(minX, eval(f, minX));
        }
        float leftX, leftY;
        float rightX = graph.topX(), rightY = graph.topY();
        int nEval = 1;
        while (true) {
            leftX = rightX;
            leftY = rightY;
            if (leftX > maxX) {
                break;
            }
            if (next.empty()) {
                float x = leftX + maxStep;
                next.push(x, eval(f, x));
                ++nEval;
            }
            rightX = next.topX();
            rightY = next.topY();
            next.pop();

            if (leftY != leftY && rightY != rightY) { // NaN
                continue;
            }

            float dx = rightX - leftX;
            float middleX = (leftX + rightX) / 2;
            float middleY = eval(f, middleX);
            ++nEval;
            boolean middleIsOutside = (middleY < leftY && middleY < rightY)
                    || (leftY < middleY && rightY < middleY);
            if (dx < minStep) {
                if (middleIsOutside) {
                    graph.push(rightX, Float.NaN);
                }
                graph.push(rightX, rightY);
                continue;
            }
            if (middleIsOutside
                    && ((leftY < minY && rightY > maxY) || (leftY > maxY && rightY < minY))) {
                graph.push(rightX, Float.NaN);
                graph.push(rightX, rightY);
                continue;
            }

            if (!middleIsOutside) {

                if (distance2(leftX, leftY, rightX, rightY, middleY) < ythresh) {
                    graph.push(rightX, rightY);
                    continue;
                }
            }
            next.push(rightX, rightY);
            next.push(middleX, middleY);
            rightX = leftX;
            rightY = leftY;
        }
        if (!endGraph.empty()) {
            graph.append(endGraph);
        }
        long t2 = System.currentTimeMillis();

        next.clear();
        endGraph.clear();
    }

    private static Path path = new Path();

    private Path graphToPath(Data graph) {
        boolean first = true;
        int size = graph.size;
        float[] xs = graph.xs;
        float[] ys = graph.ys;
        path.rewind();
        for (int i = 0; i < size; ++i) {
            float y = ys[i];
            float x = xs[i];
            // Calculator.log("path " + x + ' ' + y);
            if (y == y) { // !NaN
                if (first) {
                    path.moveTo(x, y);
                    first = false;
                } else {
                    path.lineTo(x, y);
                }
            } else {
                first = true;
            }
        }
        return path;
    }

    private static final float NTICKS = 15;

    private static float stepFactor(float w) {
        float f = 1;
        while (w / f > NTICKS) {
            f *= 10;
        }
        while (w / f < NTICKS / 10) {
            f /= 10;
        }
        float r = w / f;
        if (r < NTICKS / 5) {
            return f / 5;
        } else if (r < NTICKS / 2) {
            return f / 2;
        } else {
            return f;
        }
    }

    private static StringBuilder b = new StringBuilder();
    private static char[] buf = new char[20];

    private static StringBuilder format(float fv) {
        int pos = 0;
        boolean addDot = false;
        int v = Math.round(fv * 100);
        boolean isNeg = v < 0;
        v = isNeg ? -v : v;
        for (int i = 0; i < 2; ++i) {
            int digit = v % 10;
            v /= 10;
            if (digit != 0 || addDot) {
                buf[pos++] = (char) ('0' + digit);
                addDot = true;
            }
        }
        if (addDot) {
            buf[pos++] = '.';
        }
        if (v == 0) {
            buf[pos++] = '0';
        }
        while (v != 0) {
            buf[pos++] = (char) ('0' + (v % 10));
            v /= 10;
        }
        if (isNeg) {
            buf[pos++] = '-';
        }
        b.setLength(0);
        b.append(buf, 0, pos);
        b.reverse();
        return b;
    }

    private void drawGraph(Canvas canvas) {
        long t1 = System.currentTimeMillis();
        float minX = currentX - gwidth / 2;
        float maxX = minX + gwidth;
        float ywidth = gwidth * height / width;
        float minY = currentY - ywidth / 2;
        float maxY = minY + ywidth;
        if (minY < boundMinY || maxY > boundMaxY) {
            float halfw = ywidth / 2;
            boundMinY = minY - halfw;
            boundMaxY = maxY + halfw;
            clearAllGraph();
        }

        canvas.drawColor(0xff000000);

        paint.setStrokeWidth(0);
        paint.setAntiAlias(false);
        paint.setStyle(Paint.Style.STROKE);

        final float h2 = height / 2f;
        final float scale = width / gwidth;

        float x0 = -minX * scale;
        boolean drawYAxis = true;
        if (x0 < 25) {
            x0 = 25;
            // drawYAxis = false;
        } else if (x0 > width - 3) {
            x0 = width - 3;
            // drawYAxis = false;
        }
        float y0 = maxY * scale;
        if (y0 < 3) {
            y0 = 3;
        } else if (y0 > height - 15) {
            y0 = height - 15;
        }

        final float tickSize = 3;
        final float y2 = y0 + tickSize;
        paint.setColor(COL_GRID);
        float step = stepFactor(gwidth);
        float v = ((int) (minX / step)) * step;
        textPaint.setColor(COL_TEXT);
        textPaint.setTextSize(12);
        textPaint.setTextAlign(Paint.Align.CENTER);
        float stepScale = step * scale;
        for (float x = (v - minX) * scale; x <= width; x += stepScale, v += step) {
            canvas.drawLine(x, 0, x, height, paint);
            if (!(-.001f < v && v < .001f)) {
                StringBuilder b = format(v);
                canvas.drawText(b, 0, b.length(), x, y2 + 10, textPaint);
            }
        }

        final float x1 = x0 - tickSize;
        v = ((int) (minY / step)) * step;
        textPaint.setTextAlign(Paint.Align.RIGHT);
        for (float y = height - (v - minY) * scale; y >= 0; y -= stepScale, v += step) {
            canvas.drawLine(0, y, width, y, paint);
            if (!(-.001f < v && v < .001f)) {
                StringBuilder b = format(v);
                canvas.drawText(b, 0, b.length(), x1, y + 4, textPaint);
            }
        }

        paint.setColor(COL_AXIS);
        if (drawYAxis) {
            canvas.drawLine(x0, 0, x0, height, paint);
        }
        canvas.drawLine(0, y0, width, y0, paint);

        matrix.reset();
        matrix.preTranslate(-currentX, -currentY);
        matrix.postScale(scale, -scale);
        matrix.postTranslate(width / 2, height / 2);

        paint.setStrokeWidth(0);
        paint.setAntiAlias(false);

        int n = Math.min(funcs.size(), GRAPHS_SIZE);
        for (int i = 0; i < n; ++i) {
            computeGraph(funcs.get(i), minX, maxX, boundMinY, boundMaxY,
                    graphs[i]);
            Path path = graphToPath(graphs[i]);
            path.transform(matrix);
            paint.setColor(COL_GRAPH[i]);
            canvas.drawPath(path, paint);
        }
        lastMinX = minX;
    }

    private boolean canZoomIn() {
        return gwidth > 1f;
    }

    private boolean canZoomOut() {
        return gwidth < 50;
    }

    private void invalidateGraphs() {
        clearAllGraph();
        boundMinY = boundMaxY = 0;
        invalidate();
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        return touchHandler != null ? touchHandler.onTouchEvent(event) : super
                .onTouchEvent(event);
    }

    public void onTouchDown(float x, float y) {
        zoomController.setVisible(true);
        if (!scroller.isFinished()) {
            scroller.abortAnimation();
        }
        lastTouchX = x;
        lastTouchY = y;
    }

    public void onTouchMove(float x, float y) {
        float deltaX = x - lastTouchX;
        float deltaY = y - lastTouchY;
        if (deltaX < -1 || deltaX > 1 || deltaY < -1 || deltaY > 1) {
            scroll(-deltaX, deltaY);
            lastTouchX = x;
            lastTouchY = y;
            invalidate();
        }
    }

    public void onTouchUp(float x, float y) {
        final float scale = width / gwidth;
        float sx = -touchHandler.velocityTracker.getXVelocity();
        float sy = touchHandler.velocityTracker.getYVelocity();
        final float asx = Math.abs(sx);
        final float asy = Math.abs(sy);
        if (asx < asy / 3) {
            sx = 0;
        } else if (asy < asx / 3) {
            sy = 0;
        }
        scroller.fling(Math.round(currentX * scale),
                Math.round(currentY * scale), Math.round(sx), Math.round(sy),
                -10000, 10000, -10000, 10000);
        invalidate();
    }

    public void onTouchZoomDown(float x1, float y1, float x2, float y2) {
        zoomTracker.start(gwidth, x1, y1, x2, y2);
    }

    public void onTouchZoomMove(float x1, float y1, float x2, float y2) {
        if (!zoomTracker.update(x1, y1, x2, y2)) {
            return;
        }
        float targetGwidth = zoomTracker.value;
        if (targetGwidth > .25f && targetGwidth < 200) {
            gwidth = targetGwidth;
        }
        invalidateGraphs();
    }

    private void scroll(float deltaX, float deltaY) {
        final float scale = gwidth / width;
        float dx = deltaX * scale;
        float dy = deltaY * scale;
        final float adx = Math.abs(dx);
        final float ady = Math.abs(dy);
        if (adx < ady / 3) {
            dx = 0;
        } else if (ady < adx / 3) {
            dy = 0;
        }
        currentX += dx;
        currentY += dy;
    }
}

El registro de errores del editor XML

java.lang.NullPointerException
    at android.widget.ZoomButtonsController.createContainer(ZoomButtonsController.java:266)
    at android.widget.ZoomButtonsController.<init>(ZoomButtonsController.java:212)
    at calculator.GraphView.<init>(GraphView.java:43)
    at sun.reflect.NativeConstructorAccessorImpl.newInstance0(    at sun.reflect.NativeConstructorAccessorImpl.newInstance(    at sun.reflect.DelegatingConstructorAccessorImpl.newInstance(    at java.lang.reflect.Constructor.newInstance(    at com.android.ide.eclipse.adt.internal.editors.layout.ProjectCallback.instantiateClass(ProjectCallback.java:422)
    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)

isInEditMode()debe usarse dentro del constructor Vista personalizada. Prueba el siguiente código:

     public class GraphView extends View implements Grapher
        {

         public GraphView(Context context, AttributeSet attrs) {
                super(context, attrs);
                if(!isInEditMode())
                 init(context);
            }

            public GraphView(Context context) {
                super(context);
               if(!isInEditMode()){
                touchHandler = new TouchHandler(this);
                init(context);
              }
            }

public class CustomTextView extends TextView {

public CustomTextView(Context context) {
    super(context);
}

public CustomTextView(Context context, AttributeSet attrs) {
    super(context, attrs);

    if (!isInEditMode()) {
        createTypeface(context, attrs); //whatever added functionality you are trying to add to Widget, call that inside this condition. 
    }

}

public CustomTextView(Context context, AttributeSet attrs, int defStyle) {
    super(context, attrs, defStyle);
}


//Typeface I wan to set to my Custom TextView It can be any other functionality of your choice

private void createTypeface(Context context, AttributeSet attrs) {

    TypedArray styledAttrs = context.obtainStyledAttributes(attrs,
            R.styleable.CustomTextView);
    String fontName = styledAttrs
            .getString(R.styleable.CustomTextView_Typeface);
    styledAttrs.recycle();

    if (fontName != null) {
        Typeface typeface = Typeface.createFromAsset(context.getAssets(),
                "fonts/" + fontName);

        setTypeface(typeface);
        styledAttrs.recycle();
    }
}

}

No se pudieron crear instancias de las siguientes clases: - com.google.android.gms.ads.AdView (Clase abierta, Mostrar excepción, Borrar caché)

Consejo: use View.isInEditMode () en sus vistas personalizadas para omitir el código o mostrar datos de muestra cuando se muestren en el IDE. Si se trata de un error inesperado, también puede intentar crear el proyecto y luego actualizar manualmente el diseño.

Exception Details java.lang.NoClassDefFoundError: 
    com/google/android/gms/ads/R$styleable   at 
    com.google.android.gms.internal.ads.zzuq.<init>(com.google.android.gms:play-services-ads-lite@@18.3.0:45)   at com.google.android.gms.internal.ads.zzxl.<init>(com.google.android.gms:play-services-ads-lite@@18.3.0:30)   at com.google.android.gms.internal.ads.zzxl.<init>(com.google.android.gms:play-services-ads-lite@@18.3.0:52)   at com.google.android.gms.internal.ads.zzxl.

<init>(com.google.android.gms:play-services-ads-lite@@18.3.0:17)   at com.google.android.gms.ads.BaseAdView.<init>(com.google.android.gms:play-services-ads-lite@@18.3.0:5)   at com.google.android.gms.ads.AdView.<init>(com.google.android.gms:play-services-ads-lite@@18.3.0:4)   at java.lang.reflect.Constructor.newInstance(Constructor.java:423)   at android.view.LayoutInflater.createViewFromTag(LayoutInflater.java:730)   at android.view.LayoutInflater.rInflate_Original(LayoutInflater.java:863)   at android.view.LayoutInflater_Delegate.rInflate(LayoutInflater_Delegate.java:72)   at android.view.LayoutInflater.rInflate(LayoutInflater.java:837)   at android.view.LayoutInflater.rInflateChildren(LayoutInflater.java:824)   at android.view.LayoutInflater.inflate(LayoutInflater.java:515)   at android.view.LayoutInflater.inflate(LayoutInflater.java:394) Copy stack to clipboard

Prueba esto, funciona para mí

public class MyOwnTextView extends TextView {

    public MyOwnTextView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
        // TODO Auto-generated constructor stub
        isInEditMode();
    }

    public MyOwnTextView(Context context, AttributeSet attrs) {
        super(context, attrs);
        // TODO Auto-generated constructor stub
        isInEditMode();
    }
    public MyOwnTextView(Context context) {
        super(context);
        // TODO Auto-generated constructor stub
        isInEditMode();
    }

    public void setTypeface(Typeface tf, int style) {
        if(!this.isInEditMode()){
        Typeface normalTypeface = Typeface.createFromAsset(getContext().getAssets(), "font/Roboto-Light.ttf");
        Typeface boldTypeface = Typeface.createFromAsset(getContext().getAssets(), "font/Roboto-Light.ttf");

        if (style == Typeface.BOLD) {
            super.setTypeface(boldTypeface/*, -1*/);
        } else {
            super.setTypeface(normalTypeface/*, -1*/);
        }
        }

    }   

}

luego en el xml

<com.xxxxx.appname.MyOwnTextView

          android:layout_width="fill_parent"
          android:layout_height="fill_parent"

        />