Android 动态tab

修改动态tab页

1.继承HorizontalScrollView类

2.代码添加tab项

3.计算tab项的宽度，调用子类的onMeasure修改宽度

4.通过OverScroller实现tab项居中效果

/* * Copyright (C) 2011 The Android Open Source Project * 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. */import static android.view.ViewGroup.LayoutParams.MATCH_PARENT;import static android.view.ViewGroup.LayoutParams.WRAP_CONTENT;import java.util.ArrayList;import android.content.Context;import android.content.res.Resources;import android.graphics.Color;import android.util.AttributeSet;import android.view.Gravity;import android.view.View;import android.view.ViewGroup;import android.widget.HorizontalScrollView;import android.widget.RadioButton;import android.widget.RadioGroup;import android.widget.RadioGroup.OnCheckedChangeListener;import com.future.wodownloadmanager.R;import com.future.wodownloadmanager.entity.CategoryEntity;/** * This widget implements the dynamic action bar tab behavior that can change * across different configurations or circumstances. */public class TabIndicator extends HorizontalScrollView {private Runnable mTabSelector;private RadioGroup mTabLayout;private int mMaxTabWidth;private int mSelectedTabIndex = 1;private OnTabSelectedListener mTabSelectedListener;private int childCount;private String tabString;private Resources mResources;public interface OnTabSelectedListener {/** * Callback when the selected tab has been reselected. *  * @param position *            Position of the current center item. */void onTabSelected(int position, String id, String name);}private final OnClickListener mTabClickListener = new OnClickListener() {public void onClick(View view) {TabView tabView = (TabView) view;setTabString(tabView.getText().toString());final int newSelected = tabView.getIndex();if (newSelected != mSelectedTabIndex) {mSelectedTabIndex = newSelected;// animateToTab(mSelectedTabIndex - 1);animateToTab(tabView);if (mTabSelectedListener != null) {mTabSelectedListener.onTabSelected(mSelectedTabIndex,tabView.getmId(), tabView.getmName());}}}};public TabIndicator(Context context) {super(context);init(context);}public TabIndicator(Context context, Resources resources) {super(context);mResources = resources;init(context);}public void setOnTabSelectedListener(OnTabSelectedListener listener) {mTabSelectedListener = listener;}private void init(Context context) {setHorizontalScrollBarEnabled(false);mTabLayout = new RadioGroup(context);mTabLayout.setOrientation(RadioGroup.HORIZONTAL);addView(mTabLayout, new ViewGroup.LayoutParams(WRAP_CONTENT,MATCH_PARENT));}public void setOnCheckedChangeListener(OnCheckedChangeListener listener) {mTabLayout.setOnCheckedChangeListener(listener);}public TabIndicator(Context context, AttributeSet attrs) {super(context, attrs);init(context);}@Overridepublic void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {final int widthMode = MeasureSpec.getMode(widthMeasureSpec);final boolean lockedExpanded = widthMode == MeasureSpec.EXACTLY;setFillViewport(lockedExpanded);final int childCount = this.childCount;// mTabLayout.getChildCount();if (childCount > 1&& (widthMode == MeasureSpec.EXACTLY || widthMode == MeasureSpec.AT_MOST)) {int screenWidth = MeasureSpec.getSize(widthMeasureSpec);// 去除中间分割线宽度screenWidth = screenWidth - (childCount - 1) * 2;if (childCount > 4) {mMaxTabWidth = (int) (screenWidth * 0.3f);} else {mMaxTabWidth = screenWidth / childCount;}} else {mMaxTabWidth = -1;}// 最后调用onMeasure方法super.onMeasure(widthMeasureSpec, heightMeasureSpec);}private void animateToTab(final View tabView) {if (tabView == null) {return;}if (mTabSelector != null) {removeCallbacks(mTabSelector);}mTabSelector = new Runnable() {public void run() {final int scrollPos = tabView.getLeft()- (getWidth() - tabView.getWidth()) / 2;smoothScrollTo(scrollPos, 0);mTabSelector = null;}};post(mTabSelector);}private void animateToTab(final int position) {final View tabView = mTabLayout.getChildAt(position);if (tabView == null) {return;}if (mTabSelector != null) {removeCallbacks(mTabSelector);}mTabSelector = new Runnable() {public void run() {final int scrollPos = tabView.getLeft()- (getWidth() - tabView.getWidth()) / 2;// DebugLog.v("TabIndicator",// "animateToTab.position=" + position + ", tabView="// + tabView + ", Left=" + tabView.getLeft()// + ", width=" + tabView.getWidth()// + ", getWidth()=" + getWidth() + ", scrollPos="// + scrollPos);smoothScrollTo(scrollPos, 0);mTabSelector = null;}};post(mTabSelector);}@Overridepublic void onAttachedToWindow() {super.onAttachedToWindow();if (mTabSelector != null) {post(mTabSelector);}}public void setTab(ArrayList<CategoryEntity> tabs) {if (tabs != null) {mTabLayout.removeAllViews();mTabLayout.clearCheck();int index = 1;String id = "";String name = "";int size = tabs.size();childCount = size;for (CategoryEntity entity : tabs) {if (index == 1) {id = entity.getId();name = entity.getName();}addTab(index, entity.getId(), entity.getName(), size == index);index++;}if (size > 0) {setTabString(name);mSelectedTabIndex = 1;mTabLayout.check(1);animateToTab(0);if (mTabSelectedListener != null) {mTabSelectedListener.onTabSelected(mSelectedTabIndex, id,name);}}requestLayout();}}public String getTabString() {return tabString;}public void setTabString(String tabString) {this.tabString = tabString;}@Overridepublic void onDetachedFromWindow() {super.onDetachedFromWindow();if (mTabSelector != null) {removeCallbacks(mTabSelector);}}private void addTab(int index, String id, String text, boolean isLast) {final TabView tabView = new TabView(getContext());tabView.mIndex = index;tabView.mId = id;tabView.mName = text;tabView.setId(index);tabView.setGravity(Gravity.CENTER_VERTICAL | Gravity.CENTER_HORIZONTAL);tabView.setPadding(0, 18, 0, 18);tabView.setBackgroundColor(Color.WHITE);// tabView.setBackgroundResource(R.drawable.selector_tab);// tabView.setTextAppearance(this.getContext(), R.style.FreeTabStyle);tabView.setTextColor(mResources.getColorStateList(R.drawable.color_tab_text));tabView.setTextSize(16);/** * <item name="android:textColor">@drawable/color_tab_text</item> <item * name="android:textSize">16sp</item> <item * name="android:textStyle">normal</item> */tabView.setFocusable(true);tabView.setOnClickListener(mTabClickListener);tabView.setText(text);mTabLayout.addView(tabView, new RadioGroup.LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.MATCH_PARENT, 1));// 添加分割线// if (!isLast) {// View line = new View(getContext());// line.setBackgroundResource(R.drawable.shadow_line);// line.setLayoutParams(new RadioGroup.LayoutParams(2,// LayoutParams.MATCH_PARENT));// mTabLayout.addView(line);// }}private class TabView extends RadioButton {private int mIndex;private String mId;private String mName;public TabView(Context context) {super(context);this.setButtonDrawable(android.R.color.transparent);}public TabView(Context context, AttributeSet attrs) {super(context, attrs);this.setButtonDrawable(android.R.color.transparent);}@Overridepublic void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {super.onMeasure(widthMeasureSpec, heightMeasureSpec);if (mMaxTabWidth > 0 && getMeasuredWidth() < mMaxTabWidth) {super.onMeasure(MeasureSpec.makeMeasureSpec(mMaxTabWidth,MeasureSpec.EXACTLY), heightMeasureSpec);}}public int getIndex() {return mIndex;}public String getmId() {return mId;}public String getmName() {return mName;}}}