This view is a scrollable and zoomable strip. It will be used for scrolling the keyboard.master
Raph Levien
11 years ago
parent
1c6027bc3b
commit
5073a65ad1
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/* |
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* Copyright 2013 Google Inc. |
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* |
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* Licensed under the Apache License, Version 2.0 (the "License"); |
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* you may not use this file except in compliance with the License. |
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* You may obtain a copy of the License at |
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* |
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* http://www.apache.org/licenses/LICENSE-2.0
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* |
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* Unless required by applicable law or agreed to in writing, software |
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* distributed under the License is distributed on an "AS IS" BASIS, |
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
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* See the License for the specific language governing permissions and |
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* limitations under the License. |
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*/ |
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package com.levien.synthesizer.android.widgets.keyboard; |
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import android.content.Context; |
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import android.graphics.Canvas; |
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import android.graphics.Paint; |
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import android.graphics.Rect; |
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import android.util.AttributeSet; |
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import android.view.MotionEvent; |
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import android.view.View; |
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public class ScrollStripView extends View { |
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public ScrollStripView(Context context, AttributeSet attrs) { |
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super(context, attrs); |
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drawingRect_ = new Rect(); |
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paint_ = new Paint(); |
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touchDown_ = new boolean[2]; |
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touchx_ = new float[2]; |
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offset_ = -2000.0f; // TODO: make more systematic
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zoom_ = 3.0f; |
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} |
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public void bindKeyboard(KeyboardView kv) { |
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keyboardView_ = kv; |
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kv.setScrollZoom(offset_, zoom_); |
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} |
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@Override |
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protected void onDraw(Canvas canvas) { |
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super.onDraw(canvas); |
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getDrawingRect(drawingRect_); |
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float x0 = 100f + offset_; |
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float x1 = x0 + 100f * zoom_; |
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paint_.setStyle(Paint.Style.STROKE); |
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canvas.drawLine(x0, drawingRect_.top, x0, drawingRect_.bottom, paint_); |
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canvas.drawLine(x1, drawingRect_.top, x1, drawingRect_.bottom, paint_); |
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} |
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private boolean onTouchDown(int id, float x) { |
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touchx_[id] = x; |
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if (!touchDown_[0] && !touchDown_[1]) { |
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deltaAtTouch_ = offset_ - x; |
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} else { |
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deltaAtTouch_ = offset_ - touchx_[0]; |
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zoomAtTouch_ = zoom_; |
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scaleAtTouch_ = zoom_ / (touchx_[1] - touchx_[0]); |
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} |
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touchDown_[id] = true; |
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return false; |
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} |
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private boolean onTouchUp(int id) { |
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touchDown_[id] = false; |
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if (touchDown_[1 - id]) { |
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// Going from 2-finger (zoom) back to 1-finger (scroll)
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deltaAtTouch_ = offset_ - touchx_[1 - id]; |
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} |
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return false; |
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} |
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@Override |
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public boolean onTouchEvent(MotionEvent event) { |
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int action = event.getAction(); |
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int actionCode = action & MotionEvent.ACTION_MASK; |
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boolean redraw = false; |
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if (actionCode == MotionEvent.ACTION_DOWN) { |
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int pointerId = event.getPointerId(0); |
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if (pointerId < 2 && pointerId >= 0) { |
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redraw = onTouchDown(pointerId, event.getX()); |
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} |
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} else if (actionCode == MotionEvent.ACTION_POINTER_DOWN) { |
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int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) |
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>> MotionEvent.ACTION_POINTER_INDEX_SHIFT; |
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int pointerId = event.getPointerId(pointerIndex); |
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if (pointerId < 2 && pointerId >= 0) { |
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redraw = onTouchDown(pointerId, event.getX(pointerIndex)); |
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} |
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} else if (actionCode == MotionEvent.ACTION_UP) { |
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int pointerId = event.getPointerId(0); |
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if (pointerId < 2 && pointerId >= 0) { |
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onTouchUp(pointerId); |
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} |
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} else if (actionCode == MotionEvent.ACTION_POINTER_UP) { |
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int pointerIndex = (action & MotionEvent.ACTION_POINTER_INDEX_MASK) |
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>> MotionEvent.ACTION_POINTER_INDEX_SHIFT; |
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int pointerId = event.getPointerId(pointerIndex); |
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if (pointerId < 2 && pointerId >= 0) { |
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onTouchUp(pointerId); |
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} |
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} else if (actionCode == MotionEvent.ACTION_MOVE) { |
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for (int pointerIndex = 0; pointerIndex < event.getPointerCount(); pointerIndex++) { |
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int pointerId = event.getPointerId(pointerIndex); |
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if (pointerId < 2 && pointerId >= 0) { |
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touchx_[pointerId] = event.getX(pointerIndex); |
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} |
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} |
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if (touchDown_[0] && !touchDown_[1]) { |
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offset_ = touchx_[0] + deltaAtTouch_; |
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redraw = true; |
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} else if (!touchDown_[0] && touchDown_[1]) { |
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offset_ = touchx_[1] + deltaAtTouch_; |
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redraw = true; |
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} else if (touchDown_[0] && touchDown_[1]) { |
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zoom_ = scaleAtTouch_ * (touchx_[1] - touchx_[0]); |
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offset_ = touchx_[0] + zoom_ / zoomAtTouch_ * deltaAtTouch_; |
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redraw = true; |
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} |
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offset_ = Math.min(0, offset_); |
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// TODO: max offset
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} |
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if (redraw) { |
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if (keyboardView_ != null) { |
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keyboardView_.setScrollZoom(offset_, zoom_); |
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} |
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invalidate(); |
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} |
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return true; |
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} |
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/** |
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* Layout measurement for this widget. |
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* This method just sets a basic minimum size and makes the widget maximized otherwise. |
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*/ |
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@Override |
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protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { |
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int widthMode = MeasureSpec.getMode(widthMeasureSpec); |
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int widthSize = MeasureSpec.getSize(widthMeasureSpec); |
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int heightMode = MeasureSpec.getMode(heightMeasureSpec); |
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int heightSize = MeasureSpec.getSize(heightMeasureSpec); |
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int width = 0; |
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int height = 0; |
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float density = getResources().getDisplayMetrics().density; |
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int maxHeight = (int) (50.0f * density + 0.5f); |
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switch (widthMode) { |
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case MeasureSpec.EXACTLY: |
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width = widthSize; |
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break; |
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case MeasureSpec.AT_MOST: |
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width = widthSize; |
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break; |
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case MeasureSpec.UNSPECIFIED: |
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width = 10; |
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break; |
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} |
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switch (heightMode) { |
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case MeasureSpec.EXACTLY: |
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height = heightSize; |
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break; |
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case MeasureSpec.AT_MOST: |
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height = Math.min(maxHeight, heightSize); |
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break; |
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case MeasureSpec.UNSPECIFIED: |
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height = 10; |
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break; |
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} |
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setMeasuredDimension(width, height); |
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} |
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Rect drawingRect_; |
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Paint paint_; |
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float offset_; |
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float zoom_; |
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// touch state
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boolean[] touchDown_; |
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float[] touchx_; |
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float deltaAtTouch_; |
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float zoomAtTouch_; |
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float scaleAtTouch_; |
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KeyboardView keyboardView_; |
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} |
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