package com.itcast.googleplayteach.ui.widget;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Typeface;
import android.support.v4.view.ViewCompat;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.support.v4.widget.EdgeEffectCompat;
import android.support.v4.widget.ScrollerCompat;
import android.util.AttributeSet;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.MotionEvent;
import android.view.VelocityTracker;
import android.view.View;
import android.view.ViewConfiguration;
import android.view.ViewGroup;
import android.view.ViewParent;
import android.view.ViewTreeObserver;
import android.widget.ImageButton;
import android.widget.TextView;
import com.itcast.googleplayteach.R;
import com.itcast.googleplayteach.ui.activity.BaseActivity;
import com.itcast.googleplayteach.utils.UIUtils;
public class PagerTab extends ViewGroup {
private ViewPager mViewPager;
private PageListener mPageListener = new PageListener();
private OnPageChangeListener mDelegatePageListener;
private BaseActivity mActivity;
private int mDividerPadding = 12;
private int mDividerWidth = 1;
private int mDividerColor = 0x1A000000;
private Paint mDividerPaint;
private int mIndicatorHeight = 4;
private int mIndicatorWidth;
private int mIndicatorLeft;
private int mIndicatorColor = 0xFF0084FF;
private Paint mIndicatorPaint;
private int mContentWidth;
private int mContentHeight;
private int mTabPadding = 24;
private int mTabTextSize = 16;
private int mTabBackgroundResId = R.drawable.bg_tab_text;
private int mTabTextColorResId = R.color.tab_text_color;
private int mTabCount;
private int mCurrentPosition = 0;
private float mCurrentOffsetPixels;
private int mSelectedPosition = 0;
private boolean mIsBeingDragged = false;
private float mLastMotionX;
private VelocityTracker mVelocityTracker;
private int mMinimumVelocity;
private int mMaximumVelocity;
private int mTouchSlop;
private ScrollerCompat mScroller;
private int mLastScrollX;
private int mMaxScrollX = 0;
private int mSplitScrollX = 0;
private EdgeEffectCompat mLeftEdge;
private EdgeEffectCompat mRightEdge;
public PagerTab(Context context) {
this(context, null);
}
public PagerTab(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public PagerTab(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
if (context instanceof BaseActivity) {
mActivity = (BaseActivity) context;
}
init();
initPaint();
}
/** 初始化一些常量 */
private void init() {
mIndicatorHeight = UIUtils.dip2px(mIndicatorHeight);
mDividerPadding = UIUtils.dip2px(mDividerPadding);
mTabPadding = UIUtils.dip2px(mTabPadding);
mDividerWidth = UIUtils.dip2px(mDividerWidth);
mTabTextSize = UIUtils.dip2px(mTabTextSize);
mScroller = ScrollerCompat.create(mActivity);
final ViewConfiguration configuration = ViewConfiguration
.get(mActivity);
mTouchSlop = configuration.getScaledTouchSlop();
mMinimumVelocity = configuration.getScaledMinimumFlingVelocity();
mMaximumVelocity = configuration.getScaledMaximumFlingVelocity();
mLeftEdge = new EdgeEffectCompat(mActivity);
mRightEdge = new EdgeEffectCompat(mActivity);
}
/** 初始化笔 */
private void initPaint() {
mIndicatorPaint = new Paint();
mIndicatorPaint.setAntiAlias(true);
mIndicatorPaint.setStyle(Paint.Style.FILL);
mIndicatorPaint.setColor(mIndicatorColor);
mDividerPaint = new Paint();
mDividerPaint.setAntiAlias(true);
mDividerPaint.setStrokeWidth(mDividerWidth);
mDividerPaint.setColor(mDividerColor);
}
/** 设置ViewPager */
public void setViewPager(ViewPager viewPager) {
if (viewPager == null || viewPager.getAdapter() == null) {
throw new IllegalStateException(
"ViewPager is null or ViewPager does not have adapter instance.");
}
mViewPager = viewPager;
onViewPagerChanged();
}
private void onViewPagerChanged() {
mViewPager.setOnPageChangeListener(mPageListener);
mTabCount = mViewPager.getAdapter().getCount();
for (int i = 0; i < mTabCount; i++) {
if (mViewPager.getAdapter() instanceof IconTabProvider) {
addIconTab(i,
((IconTabProvider) mViewPager.getAdapter())
.getPageIconResId(i));
} else {
addTextTab(i, mViewPager.getAdapter().getPageTitle(i)
.toString());
}
}
ViewTreeObserver viewTreeObserver = getViewTreeObserver();
if (viewTreeObserver != null) {
viewTreeObserver
.addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
getViewTreeObserver().removeGlobalOnLayoutListener(
this);
mCurrentPosition = mViewPager.getCurrentItem();
if (mDelegatePageListener != null) {
mDelegatePageListener
.onPageSelected(mCurrentPosition);
}
}
});
}
}
/** 设置监听,因为Tab会监听ViewPager的状态,所以不要给ViewPager设置监听了,设置给Tab,由Tab转发 */
public void setOnPageChangeListener(OnPageChangeListener listener) {
mDelegatePageListener = listener;
}
/** 添加文字tab */
private void addTextTab(final int position, String title) {
TextView tab = new TextView(mActivity);
tab.setText(title);
tab.setGravity(Gravity.CENTER);
tab.setSingleLine();
tab.setTextSize(TypedValue.COMPLEX_UNIT_PX, mTabTextSize);
tab.setTypeface(Typeface.defaultFromStyle(Typeface.BOLD));
tab.setTextColor(UIUtils.getColorStateList(mTabTextColorResId));
tab.setBackgroundDrawable(UIUtils.getDrawable(mTabBackgroundResId));
tab.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.MATCH_PARENT));
addTab(position, tab);
}
/** 添加图片icon */
private void addIconTab(final int position, int resId) {
ImageButton tab = new ImageButton(mActivity);
tab.setImageResource(resId);
tab.setLayoutParams(new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
addTab(position, tab);
}
private void addTab(final int position, View tab) {
tab.setFocusable(true);
tab.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mViewPager.setCurrentItem(position);
}
});
tab.setPadding(mTabPadding, 0, mTabPadding, 0);
addView(tab, position);
}
/** 测量时的回调 */
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
int widthSize = MeasureSpec.getSize(widthMeasureSpec)
- getPaddingLeft() - getPaddingRight();
int heightSize = MeasureSpec.getSize(heightMeasureSpec)
- getPaddingBottom() - getPaddingBottom();
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
int totalWidth = 0;
int highest = 0;
int goneChildCount = 0;
for (int i = 0; i < mTabCount; i++) {
final View child = getChildAt(i);
if (child == null || child.getVisibility() == View.GONE) {
goneChildCount--;
continue;
}
int childWidthMeasureSpec;
int childHeightMeasureSpec;
LayoutParams childLayoutParams = child.getLayoutParams();
if (childLayoutParams == null) {
childLayoutParams = new LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT);
}
if (childLayoutParams.width == LayoutParams.MATCH_PARENT) {
childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(widthSize,
MeasureSpec.EXACTLY);
} else if (childLayoutParams.width == LayoutParams.WRAP_CONTENT) {
childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(widthSize,
MeasureSpec.AT_MOST);
} else {
childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
childLayoutParams.width, MeasureSpec.EXACTLY);
}
if (childLayoutParams.height == LayoutParams.MATCH_PARENT) {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
heightSize, MeasureSpec.EXACTLY);
} else if (childLayoutParams.height == LayoutParams.WRAP_CONTENT) {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
heightSize, MeasureSpec.AT_MOST);
} else {
childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
childLayoutParams.height, MeasureSpec.EXACTLY);
}
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
int childWidth = child.getMeasuredWidth();
int childHeight = child.getMeasuredHeight();
totalWidth += childWidth;
highest = highest < childHeight ? childHeight : highest;
}
if (totalWidth <= widthSize) {
int splitWidth = (int) (widthSize
/ (mTabCount - goneChildCount + 0.0f) + 0.5f);
for (int i = 0; i < mTabCount; i++) {
final View child = getChildAt(i);
if (child == null || child.getVisibility() == View.GONE) {
continue;
}
int childWidthMeasureSpec = MeasureSpec.makeMeasureSpec(
splitWidth, MeasureSpec.EXACTLY);
int childHeightMeasureSpec = MeasureSpec.makeMeasureSpec(
child.getMeasuredHeight(), MeasureSpec.EXACTLY);
child.measure(childWidthMeasureSpec, childHeightMeasureSpec);
}
mMaxScrollX = 0;
mSplitScrollX = 0;
} else {
mMaxScrollX = totalWidth - widthSize;
mSplitScrollX = (int) (mMaxScrollX
/ (mTabCount - goneChildCount - 1.0f) + 0.5f);
}
if (widthMode == MeasureSpec.EXACTLY) {
mContentWidth = widthSize;
} else {
mContentWidth = totalWidth;
}
if (heightMode == MeasureSpec.EXACTLY) {
mContentHeight = heightSize;
} else {
mContentHeight = highest;
}
int measureWidth = mContentWidth + getPaddingLeft() + getPaddingRight();
int measureHeight = mContentHeight + getPaddingTop()
+ getPaddingBottom();
setMeasuredDimension(measureWidth, measureHeight);
}
/** 布局时的回调 */
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
if (changed) {
int height = b - t;
int left = l;
for (int i = 0; i < mTabCount; i++) {
final View child = getChildAt(i);
if (child == null || child.getVisibility() == View.GONE) {
continue;
}
int top = (int) ((height - child.getMeasuredHeight()) / 2.0f + 0.5f);
int right = left + child.getMeasuredWidth();
child.layout(left, top, right, top + child.getMeasuredHeight());
left = right;
}
}
}
/** 绘制时的回调 */
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
final int height = getHeight();
canvas.drawRect(mIndicatorLeft, height - mIndicatorHeight,
mIndicatorLeft + mIndicatorWidth, height, mIndicatorPaint);
for (int i = 0; i < mTabCount - 1; i++) {
final View child = getChildAt(i);
if (child == null || child.getVisibility() == View.GONE) {
continue;
}
if (child != null) {
canvas.drawLine(child.getRight(), mDividerPadding,
child.getRight(), mContentHeight - mDividerPadding,
mDividerPaint);
}
}
boolean needsInvalidate = false;
if (!mLeftEdge.isFinished()) {
final int restoreCount = canvas.save();
final int heightEdge = getHeight() - getPaddingTop()
- getPaddingBottom();
final int widthEdge = getWidth();
canvas.rotate(270);
canvas.translate(-heightEdge + getPaddingTop(), 0);
mLeftEdge.setSize(heightEdge, widthEdge);
needsInvalidate |= mLeftEdge.draw(canvas);
canvas.restoreToCount(restoreCount);
}
if (!mRightEdge.isFinished()) {
final int restoreCount = canvas.save();
final int widthEdge = getWidth();
final int heightEdge = getHeight() - getPaddingTop()
- getPaddingBottom();
canvas.rotate(90);
canvas.translate(-getPaddingTop(), -(widthEdge + mMaxScrollX));
mRightEdge.setSize(heightEdge, widthEdge);
needsInvalidate |= mRightEdge.draw(canvas);
canvas.restoreToCount(restoreCount);
}
if (needsInvalidate) {
postInvalidate();
}
}
/** 触摸事件是否拦截的方法 */
@Override
public boolean onInterceptTouchEvent(MotionEvent ev) {
final int action = ev.getAction();
if (mIsBeingDragged && action == MotionEvent.ACTION_MOVE) {
return true;
}
switch (action) {
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
mLastMotionX = x;
mIsBeingDragged = !mScroller.isFinished();
break;
}
case MotionEvent.ACTION_MOVE: {
final float x = ev.getX();
final int xDiff = (int) Math.abs(x - mLastMotionX);
if (xDiff > mTouchSlop) {
mIsBeingDragged = true;
mLastMotionX = x;
ViewParent parent = getParent();
if (parent != null) {
parent.requestDisallowInterceptTouchEvent(true);
}
}
break;
}
case MotionEvent.ACTION_CANCEL:
case MotionEvent.ACTION_UP:
mIsBeingDragged = false;
break;
}
return mIsBeingDragged;
}
/** 触摸事件的处理方法 */
public boolean onTouchEvent(MotionEvent ev) {
if (mVelocityTracker == null) {
mVelocityTracker = VelocityTracker.obtain();
}
mVelocityTracker.addMovement(ev);
final int action = ev.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN: {
final float x = ev.getX();
if (!mScroller.isFinished()) {
mScroller.abortAnimation();
}
mLastMotionX = x;
break;
}
case MotionEvent.ACTION_MOVE: {
final float x = ev.getX();
final float deltaX = x - mLastMotionX;
if (!mIsBeingDragged) {
if (Math.abs(deltaX) > mTouchSlop) {
mIsBeingDragged = true;
}
}
if (mIsBeingDragged) {
mLastMotionX = x;
onMove(deltaX);
}
break;
}
case MotionEvent.ACTION_UP: {
if (mIsBeingDragged) {
final VelocityTracker velocityTracker = mVelocityTracker;
velocityTracker.computeCurrentVelocity(1000, mMaximumVelocity);
float velocity = velocityTracker.getXVelocity();
onUp(velocity);
}
}
case MotionEvent.ACTION_CANCEL: {
mIsBeingDragged = false;
if (mVelocityTracker != null) {
mVelocityTracker.recycle();
mVelocityTracker = null;
}
break;
}
}
return true;
}
private void onMove(float x) {
if (mMaxScrollX <= 0) {
if (mViewPager.isFakeDragging() || mViewPager.beginFakeDrag()) {
mViewPager.fakeDragBy(x);
}
} else {
int scrollByX = -(int) (x + 0.5);
if (getScrollX() + scrollByX < 0) {
scrollByX = 0 - getScrollX();
mLeftEdge.onPull(Math.abs(x) / getWidth());
}
if (getScrollX() + scrollByX > mMaxScrollX) {
scrollByX = mMaxScrollX - getScrollX();
mRightEdge.onPull(Math.abs(x) / getWidth());
}
scrollBy(scrollByX, 0);
ViewCompat.postInvalidateOnAnimation(this);
}
}
private void onUp(float velocity) {
if (mMaxScrollX <= 0) {
if (mViewPager.isFakeDragging())
mViewPager.endFakeDrag();
} else {
if (Math.abs(velocity) <= mMinimumVelocity) {
return;
}
mScroller.fling(getScrollX(), 0, -(int) (velocity + 0.5), 0, 0,
mMaxScrollX, 0, 0, 270, 0);
ViewCompat.postInvalidateOnAnimation(this);
}
}
@Override
public void computeScroll() {
if (mScroller.computeScrollOffset()) {
int oldX = mLastScrollX;
mLastScrollX = mScroller.getCurrX();
if (mLastScrollX < 0 && oldX >= 0) {
mLeftEdge.onAbsorb((int) mScroller.getCurrVelocity());
} else if (mLastScrollX > mMaxScrollX && oldX <= mMaxScrollX) {
mRightEdge.onAbsorb((int) mScroller.getCurrVelocity());
}
int x = mLastScrollX;
if (mLastScrollX < 0) {
x = 0;
} else if (mLastScrollX > mMaxScrollX) {
x = mMaxScrollX;
}
scrollTo(x, 0);
}
ViewCompat.postInvalidateOnAnimation(this);
}
/** 检测mIndicatorOffset的合法性,并计算出其他有关tab的属性值 */
private void checkAndcalculate() {
final View firstTab = getChildAt(0);
if (mIndicatorLeft < firstTab.getLeft()) {
mIndicatorLeft = firstTab.getLeft();
mIndicatorWidth = firstTab.getWidth();
}
View lastTab = getChildAt(mTabCount - 1);
if (mIndicatorLeft > lastTab.getLeft()) {
mIndicatorLeft = lastTab.getLeft();
mIndicatorWidth = lastTab.getWidth();
}
for (int i = 0; i < mTabCount; i++) {
View tab = getChildAt(i);
if (mIndicatorLeft < tab.getLeft()) {
mCurrentPosition = i - 1;
View currentTab = getChildAt(mCurrentPosition);
mCurrentOffsetPixels = (mIndicatorLeft - currentTab.getLeft())
/ (currentTab.getWidth() + 0.0f);
break;
}
}
}
/** 滚动到指定的child */
public void scrollSelf(int position, float offset) {
if (position >= mTabCount) {
return;
}
final View tab = getChildAt(position);
mIndicatorLeft = (int) (tab.getLeft() + tab.getWidth() * offset + 0.5);
int rightPosition = position + 1;
if (offset > 0 && rightPosition < mTabCount) {
View rightTab = getChildAt(rightPosition);
mIndicatorWidth = (int) (tab.getWidth() * (1 - offset)
+ rightTab.getWidth() * offset + 0.5);
} else {
mIndicatorWidth = tab.getWidth();
}
checkAndcalculate();
int newScrollX = position * mSplitScrollX
+ (int) (offset * mSplitScrollX + 0.5);
if (newScrollX < 0) {
newScrollX = 0;
}
if (newScrollX > mMaxScrollX) {
newScrollX = mMaxScrollX;
}
int duration = 100;
if (mSelectedPosition != -1) {
duration = (Math.abs(mSelectedPosition - position)) * 100;
}
mScroller.startScroll(getScrollX(), 0, (newScrollX - getScrollX()), 0,
duration);
ViewCompat.postInvalidateOnAnimation(this);
}
/** 选中指定位置的Tab */
private void selectTab(int position) {
for (int i = 0; i < mTabCount; i++) {
View tab = getChildAt(i);
if (tab != null) {
tab.setSelected(position == i);
}
}
}
/**
* ViewPager的OnPageChangeListener实现类,因为我们需要在PagerTab中获取PagerView的监听,
* 以便可以调整tab
*/
private class PageListener implements OnPageChangeListener {
@Override
public void onPageScrolled(int position, float positionOffset,
final int positionOffsetPixels) {
scrollSelf(position, positionOffset);
if (mDelegatePageListener != null) {
mDelegatePageListener.onPageScrolled(position, positionOffset,
positionOffsetPixels);
}
}
@Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_IDLE) {
mSelectedPosition = -1;
}
if (mDelegatePageListener != null) {
mDelegatePageListener.onPageScrollStateChanged(state);
}
}
@Override
public void onPageSelected(int position) {
System.out.println("onPageSelected:" + position);
mSelectedPosition = position;
selectTab(position);
if (mDelegatePageListener != null) {
mDelegatePageListener.onPageSelected(position);
}
}
}
/** 如果指示器希望是图片,则继承该接口 */
public interface IconTabProvider {
public int getPageIconResId(int position);
public int getPageSelectedIconResId();
}
}