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/*
* Copyright (C) 2012 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.viewpagerindicator;
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.drawable.Drawable;
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;
/**
* Draws a line for each page. The current page line is colored differently
* than the unselected page lines.
*/
public class LinePageIndicator extends View implements PageIndicator {
private static final int INVALID_POINTER = -1;
private final Paint mPaintUnselected = new Paint(Paint.ANTI_ALIAS_FLAG);
private final Paint mPaintSelected = new Paint(Paint.ANTI_ALIAS_FLAG);
private ViewPager mViewPager;
private ViewPager.OnPageChangeListener mListener;
private int mCurrentPage;
private boolean mCentered;
private float mLineWidth;
private float mGapWidth;
private int mTouchSlop;
private float mLastMotionX = -1;
private int mActivePointerId = INVALID_POINTER;
private boolean mIsDragging;
public LinePageIndicator(Context context) {
this(context, null);
}
public LinePageIndicator(Context context, AttributeSet attrs) {
this(context, attrs, R.attr.vpiLinePageIndicatorStyle);
}
public LinePageIndicator(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
if (isInEditMode()) return;
final Resources res = getResources();
//Load defaults from resources
final int defaultSelectedColor = res.getColor(R.color.default_line_indicator_selected_color);
final int defaultUnselectedColor = res.getColor(R.color.default_line_indicator_unselected_color);
final float defaultLineWidth = res.getDimension(R.dimen.default_line_indicator_line_width);
final float defaultGapWidth = res.getDimension(R.dimen.default_line_indicator_gap_width);
final float defaultStrokeWidth = res.getDimension(R.dimen.default_line_indicator_stroke_width);
final boolean defaultCentered = res.getBoolean(R.bool.default_line_indicator_centered);
//Retrieve styles attributes
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.LinePageIndicator, defStyle, 0);
mCentered = a.getBoolean(R.styleable.LinePageIndicator_centered, defaultCentered);
mLineWidth = a.getDimension(R.styleable.LinePageIndicator_lineWidth, defaultLineWidth);
mGapWidth = a.getDimension(R.styleable.LinePageIndicator_gapWidth, defaultGapWidth);
setStrokeWidth(a.getDimension(R.styleable.LinePageIndicator_strokeWidth, defaultStrokeWidth));
mPaintUnselected.setColor(a.getColor(R.styleable.LinePageIndicator_unselectedColor, defaultUnselectedColor));
mPaintSelected.setColor(a.getColor(R.styleable.LinePageIndicator_selectedColor, defaultSelectedColor));
Drawable background = a.getDrawable(R.styleable.LinePageIndicator_android_background);
if (background != null) {
setBackgroundDrawable(background);
}
a.recycle();
final ViewConfiguration configuration = ViewConfiguration.get(context);
mTouchSlop = ViewConfigurationCompat.getScaledPagingTouchSlop(configuration);
}
public void setCentered(boolean centered) {
mCentered = centered;
invalidate();
}
public boolean isCentered() {
return mCentered;
}
public void setUnselectedColor(int unselectedColor) {
mPaintUnselected.setColor(unselectedColor);
invalidate();
}
public int getUnselectedColor() {
return mPaintUnselected.getColor();
}
public void setSelectedColor(int selectedColor) {
mPaintSelected.setColor(selectedColor);
invalidate();
}
public int getSelectedColor() {
return mPaintSelected.getColor();
}
public void setLineWidth(float lineWidth) {
mLineWidth = lineWidth;
invalidate();
}
public float getLineWidth() {
return mLineWidth;
}
public void setStrokeWidth(float lineHeight) {
mPaintSelected.setStrokeWidth(lineHeight);
mPaintUnselected.setStrokeWidth(lineHeight);
invalidate();
}
public float getStrokeWidth() {
return mPaintSelected.getStrokeWidth();
}
public void setGapWidth(float gapWidth) {
mGapWidth = gapWidth;
invalidate();
}
public float getGapWidth() {
return mGapWidth;
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (mViewPager == null) {
return;
}
final int count = mViewPager.getAdapter().getCount();
if (count == 0) {
return;
}
if (mCurrentPage >= count) {
setCurrentItem(count - 1);
return;
}
final float lineWidthAndGap = mLineWidth + mGapWidth;
final float indicatorWidth = (count * lineWidthAndGap) - mGapWidth;
final float paddingTop = getPaddingTop();
final float paddingLeft = getPaddingLeft();
final float paddingRight = getPaddingRight();
float verticalOffset = paddingTop + ((getHeight() - paddingTop - getPaddingBottom()) / 2.0f);
float horizontalOffset = paddingLeft;
if (mCentered) {
horizontalOffset += ((getWidth() - paddingLeft - paddingRight) / 2.0f) - (indicatorWidth / 2.0f);
}
//Draw stroked circles
for (int i = 0; i < count; i++) {
float dx1 = horizontalOffset + (i * lineWidthAndGap);
float dx2 = dx1 + mLineWidth;
canvas.drawLine(dx1, verticalOffset, dx2, verticalOffset, (i == mCurrentPage) ? mPaintSelected : mPaintUnselected);
}
}
public boolean onTouchEvent(android.view.MotionEvent ev) {
if (super.onTouchEvent(ev)) {
return true;
}
if ((mViewPager == null) || (mViewPager.getAdapter().getCount() == 0)) {
return false;
}
final int action = ev.getAction() & MotionEventCompat.ACTION_MASK;
switch (action) {
case MotionEvent.ACTION_DOWN:
mActivePointerId = MotionEventCompat.getPointerId(ev, 0);
mLastMotionX = ev.getX();
break;
case MotionEvent.ACTION_MOVE: {
final int activePointerIndex = MotionEventCompat.findPointerIndex(ev, mActivePointerId);
final float x = MotionEventCompat.getX(ev, activePointerIndex);
final float deltaX = x - mLastMotionX;
if (!mIsDragging) {
if (Math.abs(deltaX) > mTouchSlop) {
mIsDragging = true;
}
}
if (mIsDragging) {
mLastMotionX = x;
if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {
mViewPager.fakeDragBy(deltaX);
}
}
break;
}
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
if (!mIsDragging) {
final int count = mViewPager.getAdapter().getCount();
final int width = getWidth();
final float halfWidth = width / 2f;
final float sixthWidth = width / 6f;
if ((mCurrentPage > 0) && (ev.getX() < halfWidth - sixthWidth)) {
if (action != MotionEvent.ACTION_CANCEL) {
mViewPager.setCurrentItem(mCurrentPage - 1);
}
return true;
} else if ((mCurrentPage < count - 1) && (ev.getX() > halfWidth + sixthWidth)) {
if (action != MotionEvent.ACTION_CANCEL) {
mViewPager.setCurrentItem(mCurrentPage + 1);
}
return true;
}
}
mIsDragging = false;
mActivePointerId = INVALID_POINTER;
if (mViewPager.isFakeDragging()) mViewPager.endFakeDrag();
break;
case MotionEventCompat.ACTION_POINTER_DOWN: {
final int index = MotionEventCompat.getActionIndex(ev);
mLastMotionX = MotionEventCompat.getX(ev, index);
mActivePointerId = MotionEventCompat.getPointerId(ev, index);
break;
}
case MotionEventCompat.ACTION_POINTER_UP:
final int pointerIndex = MotionEventCompat.getActionIndex(ev);
final int pointerId = MotionEventCompat.getPointerId(ev, pointerIndex);
if (pointerId == mActivePointerId) {
final int newPointerIndex = pointerIndex == 0 ? 1 : 0;
mActivePointerId = MotionEventCompat.getPointerId(ev, newPointerIndex);
}
mLastMotionX = MotionEventCompat.getX(ev, MotionEventCompat.findPointerIndex(ev, mActivePointerId));
break;
}
return true;
}
@Override
public void setViewPager(ViewPager viewPager) {
if (mViewPager == viewPager) {
return;
}
if (mViewPager != null) {
//Clear us from the old pager.
mViewPager.setOnPageChangeListener(null);
}
if (viewPager.getAdapter() == null) {
throw new IllegalStateException("ViewPager does not have adapter instance.");
}
mViewPager = viewPager;
mViewPager.setOnPageChangeListener(this);
invalidate();
}
@Override
public void setViewPager(ViewPager view, int initialPosition) {
setViewPager(view);
setCurrentItem(initialPosition);
}
@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) {
if (mListener != null) {
mListener.onPageScrollStateChanged(state);
}
}
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
if (mListener != null) {
mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
}
}
@Override
public void onPageSelected(int position) {
mCurrentPage = position;
invalidate();
if (mListener != null) {
mListener.onPageSelected(position);
}
}
@Override
public void setOnPageChangeListener(ViewPager.OnPageChangeListener listener) {
mListener = listener;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
setMeasuredDimension(measureWidth(widthMeasureSpec), measureHeight(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 measureWidth(int measureSpec) {
float 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 = mViewPager.getAdapter().getCount();
result = getPaddingLeft() + getPaddingRight() + (count * mLineWidth) + ((count - 1) * mGapWidth);
//Respect AT_MOST value if that was what is called for by measureSpec
if (specMode == MeasureSpec.AT_MOST) {
result = Math.min(result, specSize);
}
}
return (int)Math.ceil(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 measureHeight(int measureSpec) {
float 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 = mPaintSelected.getStrokeWidth() + 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 (int)Math.ceil(result);
}
@Override
public void onRestoreInstanceState(Parcelable state) {
SavedState savedState = (SavedState)state;
super.onRestoreInstanceState(savedState.getSuperState());
mCurrentPage = 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 CREATOR = new Parcelable.Creator() {
@Override
public SavedState createFromParcel(Parcel in) {
return new SavedState(in);
}
@Override
public SavedState[] newArray(int size) {
return new SavedState[size];
}
};
}
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