(效果图来源于自己写的demo,双击可放大)
大家肯定对这种可滑动的导航标题并不陌生,项目中经常需要用到这种滑动切换的效果,我觉得PagerSlidingTabStrip搭配viewPager的组合最好用了。PagerSlidingTabStrip是一个开源框架,和github上面的其他开源框架使用方法一样
开源框架地址:GitHub - astuetz/PagerSlidingTabStrip: An interactive indicator to navigate between the different pages of a ViewPager
我自己习惯用eclipse写个demo,将核心源码拷贝到项目中方便查看,话不多说,上代码
核心的类PagerSlidingTabStrip
package com.baobao.pagerslidingtabstrip;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.graphics.Paint.Style;
import android.graphics.Typeface;
import android.os.Build;
import android.os.Parcel;
import android.os.Parcelable;
import android.support.v4.view.ViewPager;
import android.support.v4.view.ViewPager.OnPageChangeListener;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.ViewTreeObserver.OnGlobalLayoutListener;
import android.widget.HorizontalScrollView;
import android.widget.ImageButton;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.Locale;
public class PagerSlidingTabStrip extends HorizontalScrollView {
public interface IconTabProvider {
public int getPageIconResId(int position);
}
// @formatter:off
private static final int[] ATTRS = new int[] { android.R.attr.textSize,
android.R.attr.textColor };
// @formatter:on
private LinearLayout.LayoutParams defaultTabLayoutParams;
private LinearLayout.LayoutParams expandedTabLayoutParams;
private final PageListener pageListener = new PageListener();
public OnPageChangeListener delegatePageListener;
private LinearLayout tabsContainer;
private ViewPager pager;
private int tabCount;
private int currentPosition = 0;
private int selectedPosition = 0;
private float currentPositionOffset = 0f;
private Paint rectPaint;
private Paint dividerPaint;
private int indicatorColor = 0xFF666666;
private int underlineColor = 0x1A000000;
private int dividerColor = 0x1A000000;
private boolean shouldExpand = false;
private boolean textAllCaps = true;
private int scrollOffset = 52;
private int indicatorHeight = 8;
private int underlineHeight = 2;
private int dividerPadding = 12;
private int tabPadding = 24;
private int dividerWidth = 1;
private int tabTextSize = 12;
private int tabTextColor = 0xFF666666;
private int selectedTabTextColor = 0xFF666666;
private Typeface tabTypeface = null;
private int tabTypefaceStyle = Typeface.NORMAL;
private int lastScrollX = 0;
private int tabBackgroundResId = R.drawable.background_tab;
private Locale locale;
public PagerSlidingTabStrip(Context context) {
this(context, null);
}
public PagerSlidingTabStrip(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public PagerSlidingTabStrip(Context context, AttributeSet attrs,
int defStyle) {
super(context, attrs, defStyle);
setFillViewport(true);
setWillNotDraw(false);
tabsContainer = new LinearLayout(context);
tabsContainer.setOrientation(LinearLayout.HORIZONTAL);
tabsContainer.setLayoutParams(new LayoutParams(
LayoutParams.MATCH_PARENT, LayoutParams.MATCH_PARENT));
addView(tabsContainer);
DisplayMetrics dm = getResources().getDisplayMetrics();
scrollOffset = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, scrollOffset, dm);
indicatorHeight = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, indicatorHeight, dm);
underlineHeight = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, underlineHeight, dm);
dividerPadding = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, dividerPadding, dm);
tabPadding = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, tabPadding, dm);
dividerWidth = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_DIP, dividerWidth, dm);
tabTextSize = (int) TypedValue.applyDimension(
TypedValue.COMPLEX_UNIT_SP, tabTextSize, dm);
// get system attrs (android:textSize and android:textColor)
TypedArray a = context.obtainStyledAttributes(attrs, ATTRS);
tabTextSize = a.getDimensionPixelSize(0, tabTextSize);
tabTextColor = a.getColor(1, tabTextColor);
a.recycle();
// get custom attrs
a = context.obtainStyledAttributes(attrs,
R.styleable.PagerSlidingTabStrip);
indicatorColor = a.getColor(
R.styleable.PagerSlidingTabStrip_pstsIndicatorColor,
indicatorColor);
underlineColor = a.getColor(
R.styleable.PagerSlidingTabStrip_pstsUnderlineColor,
underlineColor);
dividerColor = a
.getColor(R.styleable.PagerSlidingTabStrip_pstsDividerColor,
dividerColor);
indicatorHeight = a.getDimensionPixelSize(
R.styleable.PagerSlidingTabStrip_pstsIndicatorHeight,
indicatorHeight);
underlineHeight = a.getDimensionPixelSize(
R.styleable.PagerSlidingTabStrip_pstsUnderlineHeight,
underlineHeight);
dividerPadding = a.getDimensionPixelSize(
R.styleable.PagerSlidingTabStrip_pstsDividerPadding,
dividerPadding);
tabPadding = a.getDimensionPixelSize(
R.styleable.PagerSlidingTabStrip_pstsTabPaddingLeftRight,
tabPadding);
tabBackgroundResId = a.getResourceId(
R.styleable.PagerSlidingTabStrip_pstsTabBackground,
tabBackgroundResId);
shouldExpand = a
.getBoolean(R.styleable.PagerSlidingTabStrip_pstsShouldExpand,
shouldExpand);
scrollOffset = a
.getDimensionPixelSize(
R.styleable.PagerSlidingTabStrip_pstsScrollOffset,
scrollOffset);
textAllCaps = a.getBoolean(
R.styleable.PagerSlidingTabStrip_pstsTextAllCaps, textAllCaps);
a.recycle();
rectPaint = new Paint();
rectPaint.setAntiAlias(true);
rectPaint.setStyle(Style.FILL);
dividerPaint = new Paint();
dividerPaint.setAntiAlias(true);
dividerPaint.setStrokeWidth(dividerWidth);
defaultTabLayoutParams = new LinearLayout.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT);
expandedTabLayoutParams = new LinearLayout.LayoutParams(0,
LayoutParams.MATCH_PARENT, 1.0f);
if (locale == null) {
locale = getResources().getConfiguration().locale;
}
}
public void setViewPager(ViewPager pager) {
this.pager = pager;
if (pager.getAdapter() == null) {
throw new IllegalStateException(
"ViewPager does not have adapter instance.");
}
pager.setOnPageChangeListener(pageListener);
notifyDataSetChanged();
}
public void setOnPageChangeListener(OnPageChangeListener listener) {
this.delegatePageListener = listener;
}
public void notifyDataSetChanged() {
tabsContainer.removeAllViews();
tabCount = pager.getAdapter().getCount();
for (int i = 0; i < tabCount; i++) {
if (pager.getAdapter() instanceof IconTabProvider) {
addIconTab(i,
((IconTabProvider) pager.getAdapter())
.getPageIconResId(i));
} else {
addTextTab(i, pager.getAdapter().getPageTitle(i).toString());
}
}
updateTabStyles();
getViewTreeObserver().addOnGlobalLayoutListener(
new OnGlobalLayoutListener() {
@Override
public void onGlobalLayout() {
getViewTreeObserver()
.removeGlobalOnLayoutListener(this);
currentPosition = pager.getCurrentItem();
scrollToChild(currentPosition, 0);
}
});
}
private void addTextTab(final int position, String title) {
TextView tab = new TextView(getContext());
tab.setText(title);
tab.setGravity(Gravity.CENTER);
tab.setSingleLine();
addTab(position, tab);
}
private void addIconTab(final int position, int resId) {
ImageButton tab = new ImageButton(getContext());
tab.setImageResource(resId);
addTab(position, tab);
}
private void addTab(final int position, View tab) {
tab.setFocusable(true);
tab.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
pager.setCurrentItem(position);
}
});
tab.setPadding(tabPadding, 0, tabPadding, 0);
tabsContainer
.addView(tab, position, shouldExpand ? expandedTabLayoutParams
: defaultTabLayoutParams);
}
private void updateTabStyles() {
for (int i = 0; i < tabCount; i++) {
View v = tabsContainer.getChildAt(i);
v.setBackgroundResource(tabBackgroundResId);
if (v instanceof TextView) {
TextView tab = (TextView) v;
tab.setTextSize(TypedValue.COMPLEX_UNIT_PX, tabTextSize);
tab.setTypeface(tabTypeface, tabTypefaceStyle);
tab.setTextColor(tabTextColor);
// setAllCaps() is only available from API 14, so the upper case
// is made manually if we are on a
// pre-ICS-build
if (textAllCaps) {
if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.ICE_CREAM_SANDWICH) {
tab.setAllCaps(true);
} else {
tab.setText(tab.getText().toString()
.toUpperCase(locale));
}
}
if (i == selectedPosition) {
tab.setTextColor(selectedTabTextColor);
}
}
}
}
private void scrollToChild(int position, int offset) {
if (tabCount == 0) {
return;
}
int newScrollX = tabsContainer.getChildAt(position).getLeft() + offset;
if (position > 0 || offset > 0) {
newScrollX -= scrollOffset;
}
if (newScrollX != lastScrollX) {
lastScrollX = newScrollX;
scrollTo(newScrollX, 0);
}
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
if (isInEditMode() || tabCount == 0) {
return;
}
final int height = getHeight();
// draw underline
rectPaint.setColor(underlineColor);
canvas.drawRect(0, height - underlineHeight, tabsContainer.getWidth(),
height, rectPaint);
// draw indicator line
rectPaint.setColor(indicatorColor);
// default: line below current tab
View currentTab = tabsContainer.getChildAt(currentPosition);
float lineLeft = currentTab.getLeft();
float lineRight = currentTab.getRight();
// if there is an offset, start interpolating left and right coordinates
// between current and next tab
if (currentPositionOffset > 0f && currentPosition < tabCount - 1) {
View nextTab = tabsContainer.getChildAt(currentPosition + 1);
final float nextTabLeft = nextTab.getLeft();
final float nextTabRight = nextTab.getRight();
lineLeft = (currentPositionOffset * nextTabLeft + (1f - currentPositionOffset)
* lineLeft);
lineRight = (currentPositionOffset * nextTabRight + (1f - currentPositionOffset)
* lineRight);
}
canvas.drawRect(lineLeft, height - indicatorHeight, lineRight, height,
rectPaint);
// draw divider
dividerPaint.setColor(dividerColor);
for (int i = 0; i < tabCount - 1; i++) {
View tab = tabsContainer.getChildAt(i);
canvas.drawLine(tab.getRight(), dividerPadding, tab.getRight(),
height - dividerPadding, dividerPaint);
}
}
private class PageListener implements OnPageChangeListener {
@Override
public void onPageScrolled(int position, float positionOffset,
int positionOffsetPixels) {
currentPosition = position;
currentPositionOffset = positionOffset;
scrollToChild(position, (int) (positionOffset * tabsContainer
.getChildAt(position).getWidth()));
invalidate();
if (delegatePageListener != null) {
delegatePageListener.onPageScrolled(position, positionOffset,
positionOffsetPixels);
}
}
@Override
public void onPageScrollStateChanged(int state) {
if (state == ViewPager.SCROLL_STATE_IDLE) {
scrollToChild(pager.getCurrentItem(), 0);
}
if (delegatePageListener != null) {
delegatePageListener.onPageScrollStateChanged(state);
}
}
@Override
public void onPageSelected(int position) {
selectedPosition = position;
updateTabStyles();
if (delegatePageListener != null) {
delegatePageListener.onPageSelected(position);
}
}
}
public void setSelectedPosition(int selectedPosition) {
this.selectedPosition = selectedPosition;
}
public void setIndicatorColor(int indicatorColor) {
this.indicatorColor = indicatorColor;
invalidate();
}
public void setIndicatorColorResource(int resId) {
this.indicatorColor = getResources().getColor(resId);
invalidate();
}
public int getIndicatorColor() {
return this.indicatorColor;
}
public void setIndicatorHeight(int indicatorLineHeightPx) {
this.indicatorHeight = indicatorLineHeightPx;
invalidate();
}
public int getIndicatorHeight() {
return indicatorHeight;
}
public void setUnderlineColor(int underlineColor) {
this.underlineColor = underlineColor;
invalidate();
}
public void setUnderlineColorResource(int resId) {
this.underlineColor = getResources().getColor(resId);
invalidate();
}
public int getUnderlineColor() {
return underlineColor;
}
public void setDividerColor(int dividerColor) {
this.dividerColor = dividerColor;
invalidate();
}
public void setDividerColorResource(int resId) {
this.dividerColor = getResources().getColor(resId);
invalidate();
}
public int getDividerColor() {
return dividerColor;
}
public void setUnderlineHeight(int underlineHeightPx) {
this.underlineHeight = underlineHeightPx;
invalidate();
}
public int getUnderlineHeight() {
return underlineHeight;
}
public void setDividerPadding(int dividerPaddingPx) {
this.dividerPadding = dividerPaddingPx;
invalidate();
}
public int getDividerPadding() {
return dividerPadding;
}
public void setScrollOffset(int scrollOffsetPx) {
this.scrollOffset = scrollOffsetPx;
invalidate();
}
public int getScrollOffset() {
return scrollOffset;
}
public void setShouldExpand(boolean shouldExpand) {
this.shouldExpand = shouldExpand;
notifyDataSetChanged();
}
public boolean getShouldExpand() {
return shouldExpand;
}
public boolean isTextAllCaps() {
return textAllCaps;
}
public void setAllCaps(boolean textAllCaps) {
this.textAllCaps = textAllCaps;
}
public void setTextSize(int textSizePx) {
this.tabTextSize = textSizePx;
updateTabStyles();
}
public int getTextSize() {
return tabTextSize;
}
public void setTextColor(int textColor) {
this.tabTextColor = textColor;
updateTabStyles();
}
public void setTextColorResource(int resId) {
this.tabTextColor = getResources().getColor(resId);
updateTabStyles();
}
public int getTextColor() {
return tabTextColor;
}
public void setSelectedTextColor(int textColor) {
this.selectedTabTextColor = textColor;
updateTabStyles();
}
public void setSelectedTextColorResource(int resId) {
this.selectedTabTextColor = getResources().getColor(resId);
updateTabStyles();
}
public int getSelectedTextColor() {
return selectedTabTextColor;
}
public void setTypeface(Typeface typeface, int style) {
this.tabTypeface = typeface;
this.tabTypefaceStyle = style;
updateTabStyles();
}
public void setTabBackground(int resId) {
this.tabBackgroundResId = resId;
updateTabStyles();
}
public int getTabBackground() {
return tabBackgroundResId;
}
public void setTabPaddingLeftRight(int paddingPx) {
this.tabPadding = paddingPx;
updateTabStyles();
}
public int getTabPaddingLeftRight() {
return tabPadding;
}
@Override
public void onRestoreInstanceState(Parcelable state) {
SavedState savedState = (SavedState) state;
super.onRestoreInstanceState(savedState.getSuperState());
currentPosition = savedState.currentPosition;
requestLayout();
}
@Override
public Parcelable onSaveInstanceState() {
Parcelable superState = super.onSaveInstanceState();
SavedState savedState = new SavedState(superState);
savedState.currentPosition = currentPosition;
return savedState;
}
static class SavedState extends BaseSavedState {
int currentPosition;
public SavedState(Parcelable superState) {
super(superState);
}
private SavedState(Parcel in) {
super(in);
currentPosition = in.readInt();
}
@Override
public void writeToParcel(Parcel dest, int flags) {
super.writeToParcel(dest, flags);
dest.writeInt(currentPosition);
}
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];
}
};
}
}