Java tutorial
/** * Copyright (c) 2016 UPTech * * Permission is hereby granted, free of charge, to any person obtaining a copy * of this software and associated documentation files (the "Software"), to deal * in the Software without restriction, including without limitation the rights * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell * copies of the Software, and to permit persons to whom the Software is * furnished to do so, subject to the following conditions: * * The above copyright notice and this permission notice shall be included in all * copies or substantial portions of the Software. * * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE * SOFTWARE. */ package org.thoughtcrime.securesms.scribbles.widget; import android.annotation.TargetApi; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.PointF; import android.os.Build; import android.support.annotation.NonNull; import android.support.annotation.Nullable; import android.support.v4.view.GestureDetectorCompat; import android.support.v4.view.ViewCompat; import android.text.Editable; import android.text.InputType; import android.text.Selection; import android.text.TextWatcher; import android.util.AttributeSet; import android.util.Log; import android.util.TypedValue; import android.view.GestureDetector; import android.view.Gravity; import android.view.MotionEvent; import android.view.ScaleGestureDetector; import android.view.View; import android.view.inputmethod.InputMethodManager; import android.widget.EditText; import android.widget.FrameLayout; import org.thoughtcrime.securesms.R; import org.thoughtcrime.securesms.scribbles.multitouch.MoveGestureDetector; import org.thoughtcrime.securesms.scribbles.multitouch.RotateGestureDetector; import org.thoughtcrime.securesms.scribbles.widget.entity.MotionEntity; import org.thoughtcrime.securesms.scribbles.widget.entity.TextEntity; import java.util.ArrayList; import java.util.List; public class MotionView extends FrameLayout implements TextWatcher { private static final String TAG = MotionView.class.getSimpleName(); public interface Constants { float SELECTED_LAYER_ALPHA = 0.15F; } public interface MotionViewCallback { void onEntitySelected(@Nullable MotionEntity entity); void onEntityDoubleTap(@NonNull MotionEntity entity); } // layers private final List<MotionEntity> entities = new ArrayList<>(); @Nullable private MotionEntity selectedEntity; private Paint selectedLayerPaint; // callback @Nullable private MotionViewCallback motionViewCallback; private EditText editText; // gesture detection private ScaleGestureDetector scaleGestureDetector; private RotateGestureDetector rotateGestureDetector; private MoveGestureDetector moveGestureDetector; private GestureDetectorCompat gestureDetectorCompat; // constructors public MotionView(Context context) { super(context); init(context, null); } public MotionView(Context context, AttributeSet attrs) { super(context, attrs); init(context, attrs); } public MotionView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(context, attrs); } @SuppressWarnings("unused") @TargetApi(Build.VERSION_CODES.LOLLIPOP) public MotionView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); init(context, attrs); } private void init(@NonNull Context context, @Nullable AttributeSet attrs) { // I fucking love Android setWillNotDraw(false); selectedLayerPaint = new Paint(); selectedLayerPaint.setAlpha((int) (255 * Constants.SELECTED_LAYER_ALPHA)); selectedLayerPaint.setAntiAlias(true); this.editText = new EditText(context, attrs); ViewCompat.setAlpha(this.editText, 0); this.editText.setLayoutParams(new LayoutParams(1, 1, Gravity.TOP | Gravity.LEFT)); this.editText.setClickable(false); this.editText.setBackgroundColor(Color.TRANSPARENT); this.editText.setTextSize(TypedValue.COMPLEX_UNIT_SP, 1); this.editText.setInputType(InputType.TYPE_TEXT_FLAG_MULTI_LINE | InputType.TYPE_TEXT_FLAG_NO_SUGGESTIONS | InputType.TYPE_TEXT_VARIATION_VISIBLE_PASSWORD); this.addView(editText); this.editText.clearFocus(); this.editText.addTextChangedListener(this); // init listeners this.scaleGestureDetector = new ScaleGestureDetector(context, new ScaleListener()); this.rotateGestureDetector = new RotateGestureDetector(context, new RotateListener()); this.moveGestureDetector = new MoveGestureDetector(context, new MoveListener()); this.gestureDetectorCompat = new GestureDetectorCompat(context, new TapsListener()); setOnTouchListener(onTouchListener); updateUI(); } public void startEditing(TextEntity entity) { editText.setFocusableInTouchMode(true); editText.setFocusable(true); editText.requestFocus(); editText.setText(entity.getLayer().getText()); Selection.setSelection(editText.getText(), editText.length()); InputMethodManager ims = (InputMethodManager) getContext().getSystemService(Context.INPUT_METHOD_SERVICE); ims.showSoftInput(editText, InputMethodManager.SHOW_IMPLICIT); } public MotionEntity getSelectedEntity() { return selectedEntity; } public List<MotionEntity> getEntities() { return entities; } public void setMotionViewCallback(@Nullable MotionViewCallback callback) { this.motionViewCallback = callback; } public void addEntity(@Nullable MotionEntity entity) { if (entity != null) { entities.add(entity); selectEntity(entity, false); } } public void addEntityAndPosition(@Nullable MotionEntity entity) { if (entity != null) { initEntityBorder(entity); initialTranslateAndScale(entity); entities.add(entity); selectEntity(entity, true); } } private void initEntityBorder(@NonNull MotionEntity entity) { // init stroke int strokeSize = getResources().getDimensionPixelSize(R.dimen.scribble_stroke_size); Paint borderPaint = new Paint(); borderPaint.setStrokeWidth(strokeSize); borderPaint.setAntiAlias(true); borderPaint.setColor(getContext().getResources().getColor(R.color.sticker_selected_color)); entity.setBorderPaint(borderPaint); } @Override protected void dispatchDraw(Canvas canvas) { super.dispatchDraw(canvas); // dispatch draw is called after child views is drawn. // the idea that is we draw background stickers, than child views (if any), and than selected item // to draw on top of child views - do it in dispatchDraw(Canvas) // to draw below that - do it in onDraw(Canvas) if (selectedEntity != null) { selectedEntity.draw(canvas, selectedLayerPaint); } } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); drawAllEntities(canvas); } public void render(Canvas canvas) { unselectEntity(); draw(canvas); } /** * draws all entities on the canvas * @param canvas Canvas where to draw all entities */ private void drawAllEntities(Canvas canvas) { for (int i = 0; i < entities.size(); i++) { entities.get(i).draw(canvas, null); } } /** * as a side effect - the method deselects Entity (if any selected) * @return bitmap with all the Entities at their current positions */ public Bitmap getThumbnailImage() { selectEntity(null, false); Bitmap bmp = Bitmap.createBitmap(getWidth(), getHeight(), Bitmap.Config.ARGB_8888); // IMPORTANT: always create white background, cos if the image is saved in JPEG format, // which doesn't have transparent pixels, the background will be black bmp.eraseColor(Color.WHITE); Canvas canvas = new Canvas(bmp); drawAllEntities(canvas); return bmp; } private void updateUI() { invalidate(); } private void handleTranslate(PointF delta) { if (selectedEntity != null) { float newCenterX = selectedEntity.absoluteCenterX() + delta.x; float newCenterY = selectedEntity.absoluteCenterY() + delta.y; // limit entity center to screen bounds boolean needUpdateUI = false; if (newCenterX >= 0 && newCenterX <= getWidth()) { selectedEntity.getLayer().postTranslate(delta.x / getWidth(), 0.0F); needUpdateUI = true; } if (newCenterY >= 0 && newCenterY <= getHeight()) { selectedEntity.getLayer().postTranslate(0.0F, delta.y / getHeight()); needUpdateUI = true; } if (needUpdateUI) { updateUI(); } } } private void initialTranslateAndScale(@NonNull MotionEntity entity) { entity.moveToCanvasCenter(); entity.getLayer().setScale(entity.getLayer().initialScale()); } private void selectEntity(@Nullable MotionEntity entity, boolean updateCallback) { if (selectedEntity != null) { selectedEntity.setIsSelected(false); if (selectedEntity instanceof TextEntity) { editText.clearComposingText(); editText.clearFocus(); InputMethodManager imm = (InputMethodManager) getContext() .getSystemService(Context.INPUT_METHOD_SERVICE); imm.hideSoftInputFromWindow(editText.getWindowToken(), 0); } } if (entity != null) { entity.setIsSelected(true); } selectedEntity = entity; invalidate(); if (updateCallback && motionViewCallback != null) { motionViewCallback.onEntitySelected(entity); } } public void unselectEntity() { if (selectedEntity != null) { selectEntity(null, false); } } @Nullable private MotionEntity findEntityAtPoint(float x, float y) { MotionEntity selected = null; PointF p = new PointF(x, y); for (int i = entities.size() - 1; i >= 0; i--) { if (entities.get(i).pointInLayerRect(p)) { selected = entities.get(i); break; } } return selected; } private void updateSelectionOnTap(MotionEvent e) { MotionEntity entity = findEntityAtPoint(e.getX(), e.getY()); selectEntity(entity, true); } private void updateOnLongPress(MotionEvent e) { // if layer is currently selected and point inside layer - move it to front if (selectedEntity != null) { PointF p = new PointF(e.getX(), e.getY()); if (selectedEntity.pointInLayerRect(p)) { bringLayerToFront(selectedEntity); } } } private void bringLayerToFront(@NonNull MotionEntity entity) { // removing and adding brings layer to front if (entities.remove(entity)) { entities.add(entity); invalidate(); } } private void moveEntityToBack(@Nullable MotionEntity entity) { if (entity == null) { return; } if (entities.remove(entity)) { entities.add(0, entity); invalidate(); } } public void flipSelectedEntity() { if (selectedEntity == null) { return; } selectedEntity.getLayer().flip(); invalidate(); } public void moveSelectedBack() { moveEntityToBack(selectedEntity); } public void deletedSelectedEntity() { if (selectedEntity == null) { return; } if (entities.remove(selectedEntity)) { selectedEntity.release(); selectedEntity = null; invalidate(); } } // memory public void release() { for (MotionEntity entity : entities) { entity.release(); } } // gesture detectors private final View.OnTouchListener onTouchListener = new View.OnTouchListener() { @Override public boolean onTouch(View v, MotionEvent event) { if (scaleGestureDetector != null) { scaleGestureDetector.onTouchEvent(event); rotateGestureDetector.onTouchEvent(event); moveGestureDetector.onTouchEvent(event); gestureDetectorCompat.onTouchEvent(event); } return true; } }; private class TapsListener extends GestureDetector.SimpleOnGestureListener { @Override public boolean onDoubleTap(MotionEvent e) { if (motionViewCallback != null && selectedEntity != null) { motionViewCallback.onEntityDoubleTap(selectedEntity); } return true; } @Override public void onLongPress(MotionEvent e) { updateOnLongPress(e); } @Override public boolean onSingleTapUp(MotionEvent e) { updateSelectionOnTap(e); return true; } } private class ScaleListener extends ScaleGestureDetector.SimpleOnScaleGestureListener { @Override public boolean onScale(ScaleGestureDetector detector) { if (selectedEntity != null) { float scaleFactorDiff = detector.getScaleFactor(); Log.w(TAG, "ScaleFactorDiff: " + scaleFactorDiff); selectedEntity.getLayer().postScale(scaleFactorDiff - 1.0F); selectedEntity.updateEntity(); updateUI(); } return true; } } private class RotateListener extends RotateGestureDetector.SimpleOnRotateGestureListener { @Override public boolean onRotate(RotateGestureDetector detector) { if (selectedEntity != null) { selectedEntity.getLayer().postRotate(-detector.getRotationDegreesDelta()); updateUI(); } return true; } } private class MoveListener extends MoveGestureDetector.SimpleOnMoveGestureListener { @Override public boolean onMove(MoveGestureDetector detector) { handleTranslate(detector.getFocusDelta()); return true; } } @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) { } @Override public void onTextChanged(CharSequence s, int start, int before, int count) { } @Override public void afterTextChanged(Editable s) { String text = s.toString(); MotionEntity entity = getSelectedEntity(); if (entity != null && entity instanceof TextEntity) { TextEntity textEntity = (TextEntity) entity; if (!textEntity.getLayer().getText().equals(text)) { textEntity.getLayer().setText(text); textEntity.updateEntity(); MotionView.this.invalidate(); } } } }