Java tutorial
/* * Copyright (C) 2014 pengjianbo(pengjianbosoft@gmail.com), Inc. * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.ez.gallery.ucrop.view.widget; import android.annotation.TargetApi; import android.content.Context; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Rect; import android.os.Build; import android.support.annotation.ColorInt; import android.support.v4.content.ContextCompat; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import com.ez.gallery.ucrop.R; /** * Created by Oleksii Shliama (https://github.com/shliama). */ public class HorizontalProgressWheelView extends View { private final Rect mCanvasClipBounds = new Rect(); private ScrollingListener mScrollingListener; private float mLastTouchedPosition; private Paint mProgressLinePaint; private int mProgressLineWidth, mProgressLineHeight; private int mProgressLineMargin; private boolean mScrollStarted; private float mTotalScrollDistance; private int mMiddleLineColor; public HorizontalProgressWheelView(Context context) { this(context, null); } public HorizontalProgressWheelView(Context context, AttributeSet attrs) { this(context, attrs, 0); } public HorizontalProgressWheelView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); init(); } @TargetApi(Build.VERSION_CODES.LOLLIPOP) public HorizontalProgressWheelView(Context context, AttributeSet attrs, int defStyleAttr, int defStyleRes) { super(context, attrs, defStyleAttr, defStyleRes); } public void setScrollingListener(ScrollingListener scrollingListener) { mScrollingListener = scrollingListener; } public void setMiddleLineColor(@ColorInt int middleLineColor) { mMiddleLineColor = middleLineColor; invalidate(); } @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: mLastTouchedPosition = event.getX(); break; case MotionEvent.ACTION_UP: if (mScrollingListener != null) { mScrollStarted = false; mScrollingListener.onScrollEnd(); } break; case MotionEvent.ACTION_MOVE: float distance = event.getX() - mLastTouchedPosition; if (distance != 0) { if (!mScrollStarted) { mScrollStarted = true; if (mScrollingListener != null) { mScrollingListener.onScrollStart(); } } onScrollEvent(event, distance); } break; } return true; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); canvas.getClipBounds(mCanvasClipBounds); int linesCount = mCanvasClipBounds.width() / (mProgressLineWidth + mProgressLineMargin); float deltaX = (mTotalScrollDistance) % (float) (mProgressLineMargin + mProgressLineWidth); mProgressLinePaint.setColor(getResources().getColor(R.color.ucrop_color_progress_wheel_line)); for (int i = 0; i < linesCount; i++) { if (i < (linesCount / 4)) { mProgressLinePaint.setAlpha((int) (255 * (i / (float) (linesCount / 4)))); } else if (i > (linesCount * 3 / 4)) { mProgressLinePaint.setAlpha((int) (255 * ((linesCount - i) / (float) (linesCount / 4)))); } else { mProgressLinePaint.setAlpha(255); } canvas.drawLine(-deltaX + mCanvasClipBounds.left + i * (mProgressLineWidth + mProgressLineMargin), mCanvasClipBounds.centerY() - mProgressLineHeight / 4.0f, -deltaX + mCanvasClipBounds.left + i * (mProgressLineWidth + mProgressLineMargin), mCanvasClipBounds.centerY() + mProgressLineHeight / 4.0f, mProgressLinePaint); } mProgressLinePaint.setColor(mMiddleLineColor); canvas.drawLine(mCanvasClipBounds.centerX(), mCanvasClipBounds.centerY() - mProgressLineHeight / 2.0f, mCanvasClipBounds.centerX(), mCanvasClipBounds.centerY() + mProgressLineHeight / 2.0f, mProgressLinePaint); } private void onScrollEvent(MotionEvent event, float distance) { mTotalScrollDistance -= distance; postInvalidate(); mLastTouchedPosition = event.getX(); if (mScrollingListener != null) { mScrollingListener.onScroll(-distance, mTotalScrollDistance); } } private void init() { mMiddleLineColor = ContextCompat.getColor(getContext(), R.color.ucrop_color_progress_wheel_line); mProgressLineWidth = getContext().getResources() .getDimensionPixelSize(R.dimen.ucrop_width_horizontal_wheel_progress_line); mProgressLineHeight = getContext().getResources() .getDimensionPixelSize(R.dimen.ucrop_height_horizontal_wheel_progress_line); mProgressLineMargin = getContext().getResources() .getDimensionPixelSize(R.dimen.ucrop_margin_horizontal_wheel_progress_line); mProgressLinePaint = new Paint(Paint.ANTI_ALIAS_FLAG); mProgressLinePaint.setStyle(Paint.Style.STROKE); mProgressLinePaint.setStrokeWidth(mProgressLineWidth); } public interface ScrollingListener { void onScrollStart(); void onScroll(float delta, float totalDistance); void onScrollEnd(); } }