tactil - zoom en pantalla android

Creando una vista de imagen dibujable y con zoom en Android

Question

Gol:

Cree una vista de imagen que se pueda dibujar y hacer zoom,

Eso significa que cuando presiono un botón para encender, es dibujable,

o cuando apago, es zoomable.

* Note que los dibujos deben alinearse con la vista de imagen

================================================== =============

Recientemente escribí una imagen de dibujo personalizable como esta:

 public class DrawView extends ImageView {

        private int color = Color.BLACK;
        private float width = 4f;
        private List<Holder> holderList = new ArrayList<Holder>();

        private class Holder {      
            Path path;
            Paint paint;

            Holder(int color, float width) {
                path = new Path();
                paint = new Paint();
                paint.setAntiAlias(true);
                paint.setStrokeWidth(width);
                paint.setColor(color);
                paint.setStyle(Paint.Style.STROKE);
                paint.setStrokeJoin(Paint.Join.ROUND);
                paint.setStrokeCap(Paint.Cap.ROUND);
            }
        }

        public DrawView(Context context) {
            super(context);
            init();
        }

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

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

        private void init() {
            holderList.add(new Holder(color, width));
        }

        @Override
        protected void onDraw(Canvas canvas) {
            super.onDraw(canvas);
            for (Holder holder : holderList) {
                canvas.drawPath(holder.path, holder.paint);
            }
        }

        @Override
        public boolean onTouchEvent(MotionEvent event) {
            float eventX = event.getX();
            float eventY = event.getY();

            switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    holderList.add(new Holder(color,width));
                    holderList.get(holderList.size() - 1).path.moveTo(eventX, eventY);
                    return true;
                case MotionEvent.ACTION_MOVE:
                    holderList.get(holderList.size() - 1).path.lineTo(eventX, eventY);
                    break;
                case MotionEvent.ACTION_UP:
                    break;
                default:
                    return false;
            }

            invalidate();
            return true;
        }

        public void resetPaths() {
            for (Holder holder : holderList) {
                holder.path.reset();
            }
            invalidate();
        }

        public void setBrushColor(int color) {
            this.color = color;
        }

        public void setWidth(float width) {
            this.width = width;
        }
    }

Y el XML es:

<com.example.tool.DrawView
    android:id="@+id/draw"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:adjustViewBounds="true" />

El problema es, ¿cómo hacer que el zoom también sea capaz ? Observe que los dibujos deben alinearse con la vista de imagen al hacer zoom .

Intente usar alguna biblioteca personalizada de imageview pero no hay suerte.

por ejemplo, cuando uso photoview, se puede hacer zoom pero los dibujos no se alinean, y el nivel de zoom se restablecerá después de que active / desactive el zoom

Además, encuentre alguna otra biblioteca como esa pero que no se ajuste al caso de vista personalizada https://github.com/matabii/scale-imageview-android

Update1: demo

Recomendada para hacer referencia a esta aplicación, la función de dibujo es en realidad la misma que estoy tratando de lograr, pero no puedo entender cómo lo hacen.

https://play.google.com/store/apps/details?id=com.zentertain.photoeditor&hl=en

Gracias

Update2: De Sandeep Maram Source

Muchas gracias Sandeep Maram, después de probar el código, todo funciona bien, lo único que queda es que los dibujos no se alinean con la vista de zoom. Por favor, eche un vistazo a la captura de pantalla

Antes de:

Después:

El círculo no se puede escalar hacia arriba o hacia abajo cuando el zoom, sería realmente bueno si lo arreglara. Además, no importa si la imagen se superpone al botón.

Answer 1

No tengo solución completa. Sin embargo, puedo sugerirle que eche un vistazo a https://github.com/chrisbanes/PhotoView que tiene implementación de zoom, y a mi CanvasView personalizado, que usé en uno de los proyectos anteriores. Permite dibujar usando la herramienta "pluma" y escribir texto en él. La función de texto no es necesaria para usted y probablemente fue demasiado específica para esa parte, por lo que puede omitirla. Tal vez te ayude. Es compatible con la rotación de la pantalla, lo que conduce a nuevas dimensiones dibujables y tanto el texto como las curvas se escalan en este caso.

public class CanvasView extends View {

    // -----------------------------------------------------------------------
    //
    // Constants
    //
    // -----------------------------------------------------------------------
    @SuppressWarnings("unused")
    private static final String TAG = CanvasView.class.getSimpleName();

    private static final String EXTRA_SUPER_STATE = "EXTRA_SUPER_STATE";
    private static final String EXTRA_COLOR = "EXTRA_COLOR";
    private static final String EXTRA_ACTION = "EXTRA_ACTION";
    private static final String EXTRA_MODIFICATIONS = "EXTRA_MODIFICATIONS";
    private static final String EXTRA_CURRENT_MODIFICATION = "EXTRA_CURRENT_MODIFICATION";

    // -----------------------------------------------------------------------
    //
    // Enums
    //
    // -----------------------------------------------------------------------
    public static enum ACTION {
        PEN, TEXT
    };

    // -----------------------------------------------------------------------
    //
    // Fields
    //
    // -----------------------------------------------------------------------
    private ArrayList<DrawableItem> mItems;
    private ACTION mAction;
    private int mColor;
    private float mDensityScale;

    private DrawableItem mCurrentItem;

    private EditText mEditText;

    // -----------------------------------------------------------------------
    //
    // Constructor
    //
    // -----------------------------------------------------------------------
    public CanvasView(Context context, AttributeSet attrs) {
        super(context, attrs);
        mItems = new ArrayList<CanvasView.DrawableItem>();
        mAction = ACTION.PEN;
        mDensityScale = getResources().getDisplayMetrics().density;
    }

    // -----------------------------------------------------------------------
    //
    // Setters
    //
    // -----------------------------------------------------------------------
    public void setAction(ACTION action) {
        if (mCurrentItem != null)
            saveCurrentModification();
        mAction = action;
        invalidate();
    }

    public void setColor(int color) {
        mColor = color;
        hideKeyboard();
    }

    public void saveCurrentModification() {
        if (mCurrentItem instanceof Curve || !((Text) mCurrentItem).isEmpty())
            mItems.add(mCurrentItem);

        mCurrentItem = null;
    }

    // -----------------------------------------------------------------------
    //
    // Methods
    //
    // -----------------------------------------------------------------------
    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        for (DrawableItem item : mItems)
            item.draw(canvas, getMeasuredWidth(), getMeasuredHeight());
        if (mCurrentItem != null)
            mCurrentItem.draw(canvas, getMeasuredWidth(), getMeasuredHeight());
    }

    @Override
    public boolean onTouchEvent(MotionEvent event) {
        switch (mAction) {
        case PEN:
            onTouchPen(event);
            break;
        case TEXT:
            onTouchText(event);
            break;
        default:
            break;
        }
        return true;

    }

    private void onTouchPen(MotionEvent event) {
        switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN:
            mCurrentItem = new Curve(mColor);
            break;
        case MotionEvent.ACTION_MOVE:
            Curve currentItem = (Curve) mCurrentItem;
            currentItem.addPoint(event.getX(), event.getY());
            break;
        case MotionEvent.ACTION_UP:
        case MotionEvent.ACTION_CANCEL:
            saveCurrentModification();
            break;
        default:
        }
        invalidate();
    }

    private void onTouchText(MotionEvent event) {
        switch (event.getActionMasked()) {
        case MotionEvent.ACTION_DOWN: {
            if (mCurrentItem != null)
                saveCurrentModification();
            mCurrentItem = new Text(new PointF(event.getX(), event.getY()),
                    mDensityScale);
            showKeyboard();
        }
            break;
        default:
        }
    }

    private void showKeyboard() {
        mEditText.setVisibility(View.VISIBLE);
        mEditText.setText("");
        mEditText.requestFocus();
        InputMethodManager inputMethodManager = (InputMethodManager) getContext()
                .getSystemService(Context.INPUT_METHOD_SERVICE);
        inputMethodManager.showSoftInput(mEditText,
                InputMethodManager.SHOW_IMPLICIT);
    }

    private void hideKeyboard() {
        mEditText.setVisibility(View.INVISIBLE);
        InputMethodManager imm = (InputMethodManager) getContext()
                .getSystemService(Context.INPUT_METHOD_SERVICE);
        imm.hideSoftInputFromWindow(mEditText.getWindowToken(), 0);
    }

    @Override
    protected Parcelable onSaveInstanceState() {
        Bundle bundle = new Bundle();
        bundle.putParcelable(EXTRA_SUPER_STATE, super.onSaveInstanceState());
        bundle.putInt(EXTRA_COLOR, mColor);
        bundle.putSerializable(EXTRA_ACTION, mAction);
        bundle.putParcelableArrayList(EXTRA_MODIFICATIONS, mItems);
        return bundle;
    }

    @Override
    protected void onRestoreInstanceState(Parcelable state) {
        if (state instanceof Bundle) {
            Bundle bundle = (Bundle) state;
            setColor(bundle.getInt(EXTRA_COLOR));
            setAction((ACTION) bundle.getSerializable(EXTRA_ACTION));
            mItems = bundle.getParcelableArrayList(EXTRA_MODIFICATIONS);
            super.onRestoreInstanceState(bundle
                    .getParcelable(EXTRA_SUPER_STATE));
            return;
        } else
            super.onRestoreInstanceState(state);
    }

    public OnEditorActionListener getEditorActionListener() {
        return mEditorActionListener;
    }

    public TextWatcher getTextWatcher() {
        return mTextWatcher;
    }

    public void setTextProvider(EditText editText) {
        mEditText = editText;
        mEditText.setOnEditorActionListener(getEditorActionListener());
        mEditText.addTextChangedListener(mTextWatcher);
    }

    public void clearSession() {
        mItems.clear();
        mCurrentItem = null;
        hideKeyboard();
        invalidate();
    }

    // -----------------------------------------------------------------------
    //
    // Listeners
    //
    // -----------------------------------------------------------------------
    private OnEditorActionListener mEditorActionListener = new OnEditorActionListener() {
        public boolean onEditorAction(TextView v, int actionId, KeyEvent event) {
            if (actionId == EditorInfo.IME_ACTION_DONE) {
                saveCurrentModification();
                hideKeyboard();
            }
            return false;
        }
    };

    private TextWatcher mTextWatcher = new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before,
                int count) {
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
        }

        @Override
        public void afterTextChanged(Editable s) {
            if (mCurrentItem instanceof Text) {
                ((Text) mCurrentItem).setText(s.toString());
                invalidate();
            }
        }
    };

    // -----------------------------------------------------------------------
    //
    // Inner classes
    //
    // -----------------------------------------------------------------------
    public static interface OnStartTextInputListener {
        public void onTextInputStarted(CanvasView view);
    }

    private static interface DrawableItem extends Parcelable {
        public void draw(Canvas canvas, float viewWidth, float viewHeight);
    }

    private static class Curve implements DrawableItem {
        // -----------------------------------------------------------------------
        //
        // Fields
        //
        // -----------------------------------------------------------------------
        private ArrayList<PointF> mPoints;
        private int mColor;
        private Paint mPaint;

        // -----------------------------------------------------------------------
        //
        // Constructor
        //
        // -----------------------------------------------------------------------
        public Curve(int color) {
            mPoints = new ArrayList<PointF>();
            mColor = color;
            mPaint = new Paint();
            mPaint.setColor(mColor);
            mPaint.setStrokeWidth(2);
        }

        private Curve(Parcel parcel) {
            mColor = parcel.readInt();
            parcel.readList(mPoints, PointF.class.getClassLoader());
        }

        // -----------------------------------------------------------------------
        //
        // Methods
        //
        // -----------------------------------------------------------------------
        @Override
        public void draw(Canvas canvas, float viewWidth, float viewHeight) {
            for (int i = 1; i < mPoints.size(); ++i) {
                PointF prev = mPoints.get(i - 1);
                PointF current = mPoints.get(i);
                canvas.drawLine(prev.x / viewWidth * canvas.getWidth(), prev.y
                        / viewHeight * canvas.getHeight(), current.x
                        / viewWidth * canvas.getWidth(), current.y / viewHeight
                        * canvas.getHeight(), mPaint);
            }
        }

        public void addPoint(float x, float y) {
            mPoints.add(new PointF(x, y));
        }

        @Override
        public int describeContents() {
            return 0;
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
            dest.writeInt(mColor);
            dest.writeList(mPoints);
        }

        // -----------------------------------------------------------------------
        //
        // Inner classes
        //
        // -----------------------------------------------------------------------
        public static final Parcelable.Creator<Curve> CREATOR = new Parcelable.Creator<Curve>() {
            public Curve createFromParcel(Parcel in) {
                return new Curve(in);
            }

            public Curve[] newArray(int size) {
                return new Curve[size];
            }
        };
    }

    private static class Text implements DrawableItem {
        // -----------------------------------------------------------------------
        //
        // Constatns
        //
        // -----------------------------------------------------------------------
        private static final int FONT_SIZE = 14;
        private static final int PADDING = 4;
        private static final int BORDER_WIDTH = 2;
        private static final int BORDER_COLOR = Color.rgb(0, 0, 0);
        private static final int BOX_COLOR = Color.rgb(255, 255, 255);
        private static final int FONT_COLOR = Color.rgb(0, 0, 0);

        // -----------------------------------------------------------------------
        //
        // Fields
        //
        // -----------------------------------------------------------------------
        private Paint mBoxPaint;
        private Paint mBorderPaint;
        private Paint mTextPaint;

        private float mDensityScale;

        private PointF mPoint;
        private String mTextString = "";

        // -----------------------------------------------------------------------
        //
        // Constructor
        //
        // -----------------------------------------------------------------------
        public Text(PointF point, float densityScale) {
            mPoint = point;
            mDensityScale = densityScale;

            mBoxPaint = new Paint();
            mBoxPaint.setStyle(Style.FILL);
            mBoxPaint.setColor(BOX_COLOR);

            mBorderPaint = new Paint();
            mBorderPaint.setStyle(Style.STROKE);
            mBorderPaint.setColor(BORDER_COLOR);
            mBorderPaint.setStrokeWidth(getBorderWidth());

            mTextPaint = new Paint();
            mTextPaint.setTextSize(getFontSize());
            mTextPaint.setAntiAlias(true);
            mTextPaint.setTextAlign(Paint.Align.LEFT);
            mTextPaint.setColor(FONT_COLOR);
        }

        // -----------------------------------------------------------------------
        //
        // Methods
        //
        // -----------------------------------------------------------------------
        public void setText(String text) {
            mTextString = text;
        }

        public boolean isEmpty() {
            return Utils.isEmpty(mTextString);
        }

        @Override
        public int describeContents() {
            return 0;
        }

        @Override
        public void writeToParcel(Parcel dest, int flags) {
        }

        private float getFontSize() {
            return FONT_SIZE * mDensityScale;
        }

        private float getPadding() {
            return PADDING * mDensityScale;
        }

        private float getBorderWidth() {
            return BORDER_WIDTH * mDensityScale;
        }

        private float getStringWidth(String string) {
            Rect bounds = new Rect();
            mTextPaint.getTextBounds(string, 0, string.length(), bounds);
            return bounds.width();
        }

        @Override
        public void draw(Canvas canvas, float viewWidth, float viewHeight) {
            ArrayList<String> labelList = new ArrayList<String>();

            String[] lines = mTextString.split(" ");
            String prevLine = "";
            float textHeight = (2 * getBorderWidth() + 2 * getPadding())
                    / viewHeight * canvas.getHeight();
            float textWidth = 0;
            for (int i = 0; i < lines.length; ++i) {
                String string = lines[i];
                String newline = prevLine.concat(" " + string).trim();

                float prevLineWidth = (getStringWidth(prevLine) + 2
                        * getBorderWidth() + 2 * getPadding())
                        / viewWidth * canvas.getWidth();
                float newLineWidth = (getStringWidth(newline) + 2
                        * getBorderWidth() + 2 * getPadding())
                        / viewWidth * canvas.getWidth();
                float availableWidth = canvas.getWidth() - mPoint.x / viewWidth
                        * canvas.getWidth() + 1;

                if (newLineWidth > availableWidth) {
                    if (!Utils.isEmpty(prevLine)) {
                        labelList.add(prevLine);
                        textHeight += (getFontSize() + getPadding())
                                / viewHeight * canvas.getHeight();
                        if (prevLineWidth >= textWidth)
                            textWidth = prevLineWidth;
                    }
                    prevLine = string;
                    if (i == lines.length - 1) {
                        prevLineWidth = (getStringWidth(prevLine) + 2
                                * getBorderWidth() + 2 * getPadding())
                                / viewWidth * canvas.getWidth();
                        labelList.add(prevLine);
                        if (prevLineWidth > textWidth)
                            textWidth = prevLineWidth;
                        textHeight += getFontSize() / viewHeight
                                * canvas.getHeight();
                    }
                } else if (i == lines.length - 1) {
                    labelList.add(newline);
                    if (newLineWidth > textWidth)
                        textWidth = newLineWidth;
                    textHeight += getFontSize() / viewHeight
                            * canvas.getHeight();
                } else {
                    prevLine = newline;
                }

            }

            textHeight = Math.min(textHeight, canvas.getHeight() - mPoint.y
                    / viewHeight * canvas.getHeight());
            textWidth = Math.min(textWidth, canvas.getWidth() - mPoint.x
                    / viewWidth * canvas.getWidth());
            if (isEmpty()) {
                textWidth = (getPadding() * 2 + getBorderWidth() * 2)
                        / viewWidth * canvas.getWidth();
            }
            canvas.drawRect(mPoint.x / viewWidth * canvas.getWidth(), mPoint.y
                    / viewHeight * canvas.getHeight(), mPoint.x / viewWidth
                    * canvas.getWidth() + textWidth, mPoint.y / viewHeight
                    * canvas.getHeight() + textHeight, mBoxPaint);
            mBorderPaint.setStrokeWidth(getBorderWidth() / viewWidth
                    * canvas.getWidth());
            canvas.drawRect(mPoint.x / viewWidth * canvas.getWidth(), mPoint.y
                    / viewHeight * canvas.getHeight(), mPoint.x / viewWidth
                    * canvas.getWidth() + textWidth, mPoint.y / viewHeight
                    * canvas.getHeight() + textHeight, mBorderPaint);
            mBorderPaint.setStrokeWidth(getBorderWidth());
            float offset = (getBorderWidth() + getPadding() + getFontSize())
                    / viewWidth * canvas.getWidth();
            mTextPaint.setTextSize(getFontSize() / viewHeight
                    * canvas.getHeight());
            for (String string : labelList) {
                canvas.drawText(string, (mPoint.x + getBorderWidth())
                        / viewWidth * canvas.getWidth(), mPoint.y / viewHeight
                        * canvas.getHeight() + offset, mTextPaint);
                offset += (getFontSize() + getPadding()) / viewHeight
                        * canvas.getHeight();
            }
            mTextPaint.setTextSize(getFontSize());
        }
    }

Answer 2

Respuesta actualizada con zoom habilitar / deshabilitar y dibujar vista

activity_main.xml

<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context=".MainActivity" >
<Button 
    android:id="@+id/enable_zoom"
    android:layout_height="wrap_content"
    android:layout_width="wrap_content"
    android:text="disable zoom"/>

<com.rbt.zoomdraw.CustomImageView
    android:id="@+id/zoom_iv"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:src="@drawable/ic_launcher"
    android:layout_below="@+id/enable_zoom" />

<com.rbt.zoomdraw.DrawableView
    android:id="@+id/drawble_view"
    android:layout_width="wrap_content"
    android:layout_height="match_parent"
    android:layout_alignBottom="@+id/zoom_iv"
    android:layout_alignTop="@+id/zoom_iv" />

MainActivity.java

public class MainActivity extends Activity implements OnClickListener {

private Button enableZoomBtn;
private DrawableView drawbleView;
private CustomImageView touchImageView;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    drawbleView = (DrawableView) findViewById(R.id.drawble_view);
    enableZoomBtn = (Button) findViewById(R.id.enable_zoom);
    touchImageView = (CustomImageView) findViewById(R.id.zoom_iv);
    enableZoomBtn.setOnClickListener(this);
    drawbleView.setDrawingEnabled(false);
}
@Override
public void onClick(View v) {
    int id = v.getId();
    switch (id) {
    case R.id.enable_zoom:
        if(enableZoomBtn.getText().equals("disable zoom")){
            touchImageView.setZoomEnable(false);
            drawbleView.setDrawingEnabled(true);
            enableZoomBtn.setText("enable zoom");
        } else{
            touchImageView.setZoomEnable(true);
            drawbleView.setDrawingEnabled(false);
            enableZoomBtn.setText("disable zoom");
        }
        break;

    default:
        break;
    }
  }
}

DrawableView.java

public class DrawableView extends View {
public int width;
public  int height;
private boolean isEditable;
private Path drawPath;
private Paint drawPaint;
private Paint canvasPaint;
private Canvas drawCanvas;
private Bitmap canvasBitmap;
private int paintColor = Color.RED;
public DrawableView(Context context) {
    super(context);
}
public DrawableView(Context context, AttributeSet attrs) {
    super(context, attrs);
    this.canvasPaint = new Paint(Paint.DITHER_FLAG);
    setupDrawing();
}
public DrawableView(Context context, AttributeSet attrs, int defStyleAttr) {
    super(context, attrs, defStyleAttr);
}
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
    super.onSizeChanged(w, h, oldw, oldh);
    this.height = h;
    this.width = w;
    canvasBitmap = Bitmap.createBitmap(w, h, Bitmap.Config.ARGB_8888);
    drawCanvas = new Canvas(canvasBitmap);
}
private void setupDrawing() {
    drawPath = new Path();
    drawPaint = new Paint();
    drawPaint.setColor(paintColor);
    drawPaint.setAntiAlias(true);
    drawPaint.setDither(true);
    drawPaint.setStyle(Paint.Style.STROKE);
    drawPaint.setStrokeJoin(Paint.Join.ROUND);
    drawPaint.setStrokeCap(Paint.Cap.ROUND);
    drawPaint.setStrokeWidth(10);
}
public void setDrawingEnabled(boolean isEditable){
    this.isEditable = isEditable;
}
@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawBitmap(canvasBitmap, 0, 0, canvasPaint);
    canvas.drawPath(drawPath, drawPaint);
}

@Override
public boolean onTouchEvent(MotionEvent event) {
    if(isEditable){
        float touchX = event.getX();
        float touchY = event.getY();
        switch (event.getAction()) {
        case MotionEvent.ACTION_DOWN:
            drawPath.moveTo(touchX, touchY);
            break;
        case MotionEvent.ACTION_MOVE:
            drawPath.lineTo(touchX, touchY);
            break;
        case MotionEvent.ACTION_UP:
            drawPath.lineTo(touchX, touchY);
            drawCanvas.drawPath(drawPath, drawPaint);
            drawPath = new Path();
            break;
        default:
            return false;
        }
    } else{
        return false;
    }
    invalidate();
    return true;
  }
}

CustomImageView

public class CustomImageView extends ImageView {
Matrix matrix;
// We can be in one of these 3 states
static final int NONE = 0;
static final int DRAG = 1;
static final int ZOOM = 2;
int mode = NONE;
private boolean zoomEnable= true;
// Remember some things for zooming
PointF last = new PointF();
PointF start = new PointF();
float minScale = 1f;
float maxScale = 5f;
float[] m;

int viewWidth, viewHeight;
static final int CLICK = 3;
float saveScale = 1f;
protected float origWidth, origHeight;
int oldMeasuredWidth, oldMeasuredHeight;
ScaleGestureDetector mScaleDetector;
Context context;
public CustomImageView(Context context) {
    super(context);
    sharedConstructing(context);
}
public void setZoomEnable(boolean status){
    zoomEnable = status;
}
public CustomImageView(Context context, AttributeSet attrs) {
    super(context, attrs);
    sharedConstructing(context);
}

private void sharedConstructing(Context context) {
    super.setClickable(true);
    this.context = context;
    mScaleDetector = new ScaleGestureDetector(context, new ScaleListener());
    matrix = new Matrix();
    m = new float[9];
    setImageMatrix(matrix);
    setScaleType(ScaleType.MATRIX);

    setOnTouchListener(new OnTouchListener() {
        @Override
        public boolean onTouch(View v, MotionEvent event) {
            if(zoomEnable){
                mScaleDetector.onTouchEvent(event);
                PointF curr = new PointF(event.getX(), event.getY());

                switch (event.getAction()) {
                case MotionEvent.ACTION_DOWN:
                    last.set(curr);
                    start.set(last);
                    mode = DRAG;
                    break;

                case MotionEvent.ACTION_MOVE:
                    if (mode == DRAG) {
                        float deltaX = curr.x - last.x;
                        float deltaY = curr.y - last.y;
                        float fixTransX = getFixDragTrans(deltaX, viewWidth,
                                origWidth * saveScale);
                        float fixTransY = getFixDragTrans(deltaY, viewHeight,
                                origHeight * saveScale);
                        matrix.postTranslate(fixTransX, fixTransY);
                        fixTrans();
                        last.set(curr.x, curr.y);
                    }
                    break;

                case MotionEvent.ACTION_UP:
                    mode = NONE;
                    int xDiff = (int) Math.abs(curr.x - start.x);
                    int yDiff = (int) Math.abs(curr.y - start.y);
                    if (xDiff < CLICK && yDiff < CLICK)
                        performClick();
                    break;

                case MotionEvent.ACTION_POINTER_UP:
                    mode = NONE;
                    break;
                }

                setImageMatrix(matrix);
                invalidate();
                return true; // indicate event was handled

            } else{
                return false;
            }
        }

    });
}

public void setMaxZoom(float x) {
    maxScale = x;
}

private class ScaleListener extends
ScaleGestureDetector.SimpleOnScaleGestureListener {
    @Override
    public boolean onScaleBegin(ScaleGestureDetector detector) {
        mode = ZOOM;
        return true;
    }

    @Override
    public boolean onScale(ScaleGestureDetector detector) {
        float mScaleFactor = detector.getScaleFactor();
        float origScale = saveScale;
        saveScale *= mScaleFactor;
        if (saveScale > maxScale) {
            saveScale = maxScale;
            mScaleFactor = maxScale / origScale;
        } else if (saveScale < minScale) {
            saveScale = minScale;
            mScaleFactor = minScale / origScale;
        }

        if (origWidth * saveScale <= viewWidth
                || origHeight * saveScale <= viewHeight)
            matrix.postScale(mScaleFactor, mScaleFactor, viewWidth / 2,
                    viewHeight / 2);
        else
            matrix.postScale(mScaleFactor, mScaleFactor,
                    detector.getFocusX(), detector.getFocusY());

        fixTrans();
        return true;
    }
}

void fixTrans() {
    matrix.getValues(m);
    float transX = m[Matrix.MTRANS_X];
    float transY = m[Matrix.MTRANS_Y];

    float fixTransX = getFixTrans(transX, viewWidth, origWidth * saveScale);
    float fixTransY = getFixTrans(transY, viewHeight, origHeight
            * saveScale);

    if (fixTransX != 0 || fixTransY != 0)
        matrix.postTranslate(fixTransX, fixTransY);
}

float getFixTrans(float trans, float viewSize, float contentSize) {
    float minTrans, maxTrans;

    if (contentSize <= viewSize) {
        minTrans = 0;
        maxTrans = viewSize - contentSize;
    } else {
        minTrans = viewSize - contentSize;
        maxTrans = 0;
    }

    if (trans < minTrans)
        return -trans + minTrans;
    if (trans > maxTrans)
        return -trans + maxTrans;
    return 0;
}

float getFixDragTrans(float delta, float viewSize, float contentSize) {
    if (contentSize <= viewSize) {
        return 0;
    }
    return delta;
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
    viewWidth = MeasureSpec.getSize(widthMeasureSpec);
    viewHeight = MeasureSpec.getSize(heightMeasureSpec);

    //
    // Rescales image on rotation
    //
    if (oldMeasuredHeight == viewWidth && oldMeasuredHeight == viewHeight
            || viewWidth == 0 || viewHeight == 0)
        return;
    oldMeasuredHeight = viewHeight;
    oldMeasuredWidth = viewWidth;

    if (saveScale == 1) {
        // Fit to screen.
        float scale;

        Drawable drawable = getDrawable();
        if (drawable == null || drawable.getIntrinsicWidth() == 0
                || drawable.getIntrinsicHeight() == 0)
            return;
        int bmWidth = drawable.getIntrinsicWidth();
        int bmHeight = drawable.getIntrinsicHeight();

        Log.d("bmSize", "bmWidth: " + bmWidth + " bmHeight : " + bmHeight);

        float scaleX = (float) viewWidth / (float) bmWidth;
        float scaleY = (float) viewHeight / (float) bmHeight;
        scale = Math.min(scaleX, scaleY);
        matrix.setScale(scale, scale);

        // Center the image
        float redundantYSpace = (float) viewHeight
                - (scale * (float) bmHeight);
        float redundantXSpace = (float) viewWidth
                - (scale * (float) bmWidth);
        redundantYSpace /= (float) 2;
        redundantXSpace /= (float) 2;

        matrix.postTranslate(redundantXSpace, redundantYSpace);

        origWidth = viewWidth - 2 * redundantXSpace;
        origHeight = viewHeight - 2 * redundantYSpace;
        setImageMatrix(matrix);
     }
    fixTrans();
  }
}

Espero que funcione para usted.