Java tutorial
/* * Copyright (C) 2011 Patrik Akerfeldt * Copyright (C) 2011 Jake Wharton * * 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.dev.nutclass.view.pager; import static android.graphics.Paint.ANTI_ALIAS_FLAG; import static android.widget.LinearLayout.HORIZONTAL; import static android.widget.LinearLayout.VERTICAL; import android.annotation.TargetApi; import android.content.Context; import android.content.res.Resources; import android.content.res.TypedArray; import android.graphics.Canvas; import android.graphics.Paint; import android.graphics.Paint.Style; import android.graphics.drawable.Drawable; import android.os.Build; import android.os.Parcel; import android.os.Parcelable; import android.support.v4.view.MotionEventCompat; import android.support.v4.view.ViewConfigurationCompat; import android.support.v4.view.ViewPager; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import android.view.ViewConfiguration; import android.view.ViewParent; import com.dev.nutclass.R; import com.dev.nutclass.utils.LogUtil; /** * Draws circles (one for each view). The current view position is filled and * others are only stroked. */ public class CirclePageIndicator extends View implements PageIndicator { private static final int INVALID_POINTER = -1; private static final String TAG = "CirclePageIndicator"; private float mRadius; //?? private final Paint mPaintPageFill = new Paint(ANTI_ALIAS_FLAG); //?? private final Paint mPaintStroke = new Paint(ANTI_ALIAS_FLAG); //?? private final Paint mPaintFill = new Paint(ANTI_ALIAS_FLAG); private ViewPager mViewPager; private ViewPager.OnPageChangeListener mListener; private int mCurrentPage; private int mSnapPage; private float mPageOffset; private int mScrollState; private int mOrientation; private boolean mCentered; private boolean mSnap;//true:??false? private int mTouchSlop; private float mLastMotionX = -1; private int mActivePointerId = INVALID_POINTER; private boolean mIsDragging; private float interval = 0;// private int count; private int num; public CirclePageIndicator(Context context) { this(context, null); } public CirclePageIndicator(Context context, AttributeSet attrs) { this(context, attrs, R.attr.vpiCirclePageIndicatorStyle); } public CirclePageIndicator(Context context, AttributeSet attrs, int defStyle) { super(context, attrs, defStyle); if (isInEditMode()) return; // Load defaults from resources final Resources res = getResources(); final int defaultPageColor = res.getColor(R.color.circle_page_indicator_page_color); final int defaultFillColor = res.getColor(R.color.circle_page_indicator_fill_color); final int defaultOrientation = res.getInteger(R.integer.circle_indicator_orientation); final int defaultStrokeColor = res.getColor(R.color.circle_page_indicator_stroke_color); final float defaultStrokeWidth = res.getDimension(R.dimen.circle_indicator_stroke_width); final float defaultRadius = res.getDimension(R.dimen.circle_indicator_radius); final boolean defaultCentered = res.getBoolean(R.bool.circle_indicator_centered); final boolean defaultSnap = res.getBoolean(R.bool.circle_indicator_snap); // Retrieve styles attributes TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.CirclePageIndicator, defStyle, 0); mCentered = a.getBoolean(R.styleable.CirclePageIndicator_centered, defaultCentered); mOrientation = a.getInt(R.styleable.CirclePageIndicator_android_orientation, defaultOrientation); mPaintPageFill.setStyle(Style.FILL); mPaintPageFill.setColor(a.getColor(R.styleable.CirclePageIndicator_pageColor, defaultPageColor)); mPaintStroke.setStyle(Style.STROKE); mPaintStroke.setColor(a.getColor(R.styleable.CirclePageIndicator_strokeColor, defaultStrokeColor)); mPaintStroke .setStrokeWidth(a.getDimension(R.styleable.CirclePageIndicator_strokeWidth, defaultStrokeWidth)); mPaintFill.setStyle(Style.FILL); mPaintFill.setColor(a.getColor(R.styleable.CirclePageIndicator_fillColor, defaultFillColor)); mRadius = a.getDimension(R.styleable.CirclePageIndicator_radius, defaultRadius); mSnap = a.getBoolean(R.styleable.CirclePageIndicator_snap, defaultSnap); Drawable background = a.getDrawable(R.styleable.CirclePageIndicator_android_background); if (background != null) { setBackgroundDrawable(background); } a.recycle(); final ViewConfiguration configuration = ViewConfiguration.get(context); mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration); interval = mRadius * 4; } public void setCentered(boolean centered) { mCentered = centered; invalidate(); } public boolean isCentered() { return mCentered; } public void setPageColor(int pageColor) { mPaintPageFill.setColor(pageColor); invalidate(); } public int getPageColor() { return mPaintPageFill.getColor(); } public void setFillColor(int fillColor) { mPaintFill.setColor(fillColor); invalidate(); } public int getFillColor() { return mPaintFill.getColor(); } public void setOrientation(int orientation) { switch (orientation) { case HORIZONTAL: case VERTICAL: mOrientation = orientation; requestLayout(); break; default: throw new IllegalArgumentException("Orientation must be either HORIZONTAL or VERTICAL."); } } public int getOrientation() { return mOrientation; } public void setStrokeColor(int strokeColor) { mPaintStroke.setColor(strokeColor); invalidate(); } public int getStrokeColor() { return mPaintStroke.getColor(); } public void setStrokeWidth(float strokeWidth) { mPaintStroke.setStrokeWidth(strokeWidth); invalidate(); } public float getStrokeWidth() { return mPaintStroke.getStrokeWidth(); } public void setRadius(float radius) { mRadius = radius; invalidate(); } public float getRadius() { return mRadius; } public void setSnap(boolean snap) { mSnap = snap; invalidate(); } public boolean isSnap() { return mSnap; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (mViewPager == null) { return; } if (num == 2) { count = (((BigPicPagerAdapter) mViewPager.getAdapter()).getSize()) / 2; } else { count = ((BigPicPagerAdapter) mViewPager.getAdapter()).getSize(); } if (count == 0) { return; } int offsetPage = mCurrentPage % count; int totalSize; //??padding int startPadding; int endPadding; //? float fixCoordinate;//??HorizontalyVerticalx float changeCoordinate; if (mOrientation == HORIZONTAL) { totalSize = getWidth(); startPadding = getPaddingLeft(); endPadding = getPaddingRight(); fixCoordinate = getHeight() / 2; } else { totalSize = getHeight(); startPadding = getPaddingTop(); endPadding = getPaddingBottom(); fixCoordinate = getWidth() / 2; } changeCoordinate = startPadding + mRadius; if (mCentered) { changeCoordinate = (totalSize / 2 - ((count - 1) * interval) / 2); } float dX; float dY; float pageRadius = mRadius; //? if (mPaintStroke.getStrokeWidth() > 0) { pageRadius -= mPaintStroke.getStrokeWidth() / 2.0f; } // Draw stroked circles for (int iLoop = 0; iLoop < count; iLoop++, changeCoordinate += interval) { if (mOrientation == HORIZONTAL) { dX = changeCoordinate; dY = fixCoordinate; } else { dX = fixCoordinate; dY = changeCoordinate; } // Only paint fill if not completely transparent if (mPaintPageFill.getAlpha() > 0) { canvas.drawCircle(dX, dY, pageRadius, mPaintPageFill); } // Only paint stroke if a stroke width was non-zero if (pageRadius != mRadius) { canvas.drawCircle(dX, dY, pageRadius, mPaintStroke); } } // Draw the filled circle according to the current scroll float cx = (mSnap ? offsetPage : offsetPage) * interval + mRadius; if (!mSnap) { cx += mPageOffset * interval; } // LogUtil.d(TAG, "mCurrentPage="+mCurrentPage+",offsetPage="+offsetPage); if (mOrientation == HORIZONTAL) { dX = startPadding + cx; dY = fixCoordinate; } else { dX = fixCoordinate; dY = startPadding + cx; } canvas.drawCircle(dX, dY, mRadius, mPaintFill); } @Override public void setViewPager(ViewPager view) { if (mViewPager == view) { return; } if (mViewPager != null) { mViewPager.setOnPageChangeListener(null); } if (view.getAdapter() == null) { throw new IllegalStateException("ViewPager does not have adapter instance."); } mViewPager = view; mViewPager.setOnPageChangeListener(this); invalidate(); } @Override public void setViewPager(ViewPager view, int initialPosition) { LogUtil.d(TAG, "setViewPager"); setViewPager(view); setCurrentItem(initialPosition); } public void setViewPagerNew(ViewPager view, int initialPosition, int imgNum) { LogUtil.d(TAG, "setViewPager"); setViewPager(view); setCurrentItem(initialPosition); num = imgNum; } @Override public void setCurrentItem(int item) { if (mViewPager == null) { throw new IllegalStateException("ViewPager has not been bound."); } mViewPager.setCurrentItem(item); mCurrentPage = item; invalidate(); } @Override public void notifyDataSetChanged() { invalidate(); } @Override public void onPageScrollStateChanged(int state) { mScrollState = state; if (mListener != null) { mListener.onPageScrollStateChanged(state); } } @Override public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { mCurrentPage = position; mPageOffset = positionOffset; invalidate(); if (mListener != null) { mListener.onPageScrolled(position, positionOffset, positionOffsetPixels); } } @Override public void onPageSelected(int position) { if (mSnap || mScrollState == ViewPager.SCROLL_STATE_IDLE) { mCurrentPage = position; mSnapPage = position; invalidate(); } if (mListener != null) { mListener.onPageSelected(position); } } @Override public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) { mListener = listener; } /* * (non-Javadoc) * * @see android.view.View#onMeasure(int, int) */ @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { if (mOrientation == HORIZONTAL) { setMeasuredDimension(measureLong(widthMeasureSpec), measureShort(heightMeasureSpec)); } else { setMeasuredDimension(measureShort(widthMeasureSpec), measureLong(heightMeasureSpec)); } } /** * Determines the width of this view * * @param measureSpec * A measureSpec packed into an int * @return The width of the view, honoring constraints from measureSpec */ private int measureLong(int measureSpec) { int result; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); if ((specMode == MeasureSpec.EXACTLY) || (mViewPager == null)) { // We were told how big to be result = specSize; } else { // Calculate the width according the views count final int count = ((BigPicPagerAdapter) mViewPager.getAdapter()).getSize(); result = (int) (getPaddingLeft() + getPaddingRight() + 2 * mRadius + (count - 1) * interval); // Respect AT_MOST value if that was what is called for by // measureSpec if (specMode == MeasureSpec.AT_MOST) { result = Math.min(result, specSize); } } return result; } /** * Determines the height of this view * * @param measureSpec * A measureSpec packed into an int * @return The height of the view, honoring constraints from measureSpec */ private int measureShort(int measureSpec) { int result; int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); if (specMode == MeasureSpec.EXACTLY) { // We were told how big to be result = specSize; } else { // Measure the height result = (int) (2 * mRadius + getPaddingTop() + getPaddingBottom()); // Respect AT_MOST value if that was what is called for by // measureSpec if (specMode == MeasureSpec.AT_MOST) { result = Math.min(result, specSize); } } return result; } @Override public void onRestoreInstanceState(Parcelable state) { SavedState savedState = (SavedState) state; super.onRestoreInstanceState(savedState.getSuperState()); mCurrentPage = savedState.currentPage; mSnapPage = savedState.currentPage; requestLayout(); } @Override public Parcelable onSaveInstanceState() { Parcelable superState = super.onSaveInstanceState(); SavedState savedState = new SavedState(superState); savedState.currentPage = mCurrentPage; return savedState; } static class SavedState extends BaseSavedState { int currentPage; public SavedState(Parcelable superState) { super(superState); } private SavedState(Parcel in) { super(in); currentPage = in.readInt(); } @Override public void writeToParcel(Parcel dest, int flags) { super.writeToParcel(dest, flags); dest.writeInt(currentPage); } @SuppressWarnings("UnusedDeclaration") public static final Parcelable.Creator<SavedState> CREATOR = new Parcelable.Creator<SavedState>() { @Override public SavedState createFromParcel(Parcel in) { return new SavedState(in); } @Override public SavedState[] newArray(int size) { return new SavedState[size]; } }; } }