ViewPager顶部导航
根据老师讲课写下来的，虽然老师讲课只用了2个小时，但自己跟着写和修改却用了整整一天啊，这个导航用的地方确实还真多，写上注释，记录下来！
1.主要的自定义的类，ViewPagerIndicator继承自LinearLayout
package cq.cake.customview;
import android.content.Context;
import android.content.res.TypedArray;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.CornerPathEffect;
import android.graphics.Paint;
import android.graphics.Path;
import android.support.v4.view.ViewPager;
import android.util.AttributeSet;
import android.util.DisplayMetrics;
import android.util.TypedValue;
import android.view.Gravity;
import android.view.View;
import android.view.WindowManager;
import android.widget.LinearLayout;
import android.widget.TextView;
import java.util.List;
import cq.cake.indicator.R;
/**
* My Application -- cq.cake.customview
* Created by Small Cake on 2016/3/17 10:45.
*/
public class ViewPagerIndicator extends LinearLayout {
//绘制三角形
private Paint mPaint;
//三角形的路径
private Path mPath;
//三角形的宽高
private int mTriangleWidth;
private int mTriangleHeight;
//三角形的宽度，
private static final float RADIO_TRIANGLE_WIDTH = 1/6F;
//三角形底边的最大宽度
private final int DIMENSION_TRIANGLE_WIDTH_MAX = (int) (getScreenWidth()/3*RADIO_TRIANGLE_WIDTH);
//三角形初始化偏移位置
private int mInitTranslationX;
//移动时的位置
private int mTranslationX;
//自定义属性
private int mTabVisibleCount;
private static final int COUNT_DEFAULT_TAB =4;
private int screenWidth;
//根据标题来动态的添加标题
private List<String> mTitles;
private static final int COLOR_TEXT_NORMAL = 0X77FFFFFF;
private static final int COLOR_TEXT_HIGHLIGHT = 0xFFFFFFFF;
public ViewPagerIndicator(Context context) {
this(context, null);
}
public ViewPagerIndicator(Context context, AttributeSet attrs) {
super(context, attrs);
//获取指定的tab数量
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.ViewPagerIndicator);
mTabVisibleCount = a.getInt(R.styleable.ViewPagerIndicator_visible_tab_count,COUNT_DEFAULT_TAB);
if (mTabVisibleCount<0){
mTabVisibleCount = COUNT_DEFAULT_TAB;
}
//释放资源
a.recycle();
//初始化画笔
mPaint = new Paint();
mPaint.setAntiAlias(true);//设置抗锯齿
mPaint.setColor(Color.parseColor("#ffffff"));
//设置样式为实心
mPaint.setStyle(Paint.Style.FILL);
//防止三角形太尖锐，设置拐角处为3的圆角
mPaint.setPathEffect(new CornerPathEffect(3));
}
@Override
protected void dispatchDraw(Canvas canvas) {
canvas.save();
//移动
canvas.translate(mInitTranslationX + mTranslationX, getHeight() + 2);
canvas.drawPath(mPath, mPaint);
canvas.restore();
super.dispatchDraw(canvas);
}
/**
* 在这个方法里面设置三角形的大小
* 控件的宽高发生变化时就会调用此方法
* @param w
* @param h
* @param oldw
* @param oldh
*/
@Override
protected void onSizeChanged(int w, int h, int oldw, int oldh) {
super.onSizeChanged(w, h, oldw, oldh);
//三角形底边的宽度
mTriangleWidth = (int) (w/mTabVisibleCount*RADIO_TRIANGLE_WIDTH);
mTriangleWidth = Math.min(mTriangleWidth,DIMENSION_TRIANGLE_WIDTH_MAX);
//三角形初始值的偏移量
mInitTranslationX = w/mTabVisibleCount/2-mTriangleWidth/2;
initTriangle();
}
/**
* 当xml加载完成后调用此方法
*/
@Override
protected void onFinishInflate() {
super.onFinishInflate();
//得到子菜单个数
int cCount = getChildCount();
if (cCount==0)return;
for (int i = 0; i < cCount; i++) {
View view = getChildAt(i);
LinearLayout.LayoutParams lp = (LayoutParams) view.getLayoutParams();
lp.weight = 0;
lp.width = getScreenWidth()/mTabVisibleCount;
view.setLayoutParams(lp);
}
setTabItemClick();
}
private void initTriangle() {
//初始化高度
mTriangleHeight = mTriangleWidth/2;
mPath = new Path();
mPath.moveTo(0, 0);
mPath.lineTo(mTriangleWidth, 0);
mPath.lineTo(mTriangleWidth / 2, -mTriangleHeight);
//路径的闭合
mPath.close();
}
/**
* 指示器跟随手指移动进行滚动
* @param position
* @param offset
*/
public void scroll(int position, float offset) {
int tabWidth = getWidth()/mTabVisibleCount;
mTranslationX = (int) (tabWidth*(offset+position));
//当tab移动到最后一个时
if (position>=(mTabVisibleCount - 2)&&offset>0&&getChildCount()>mTabVisibleCount){
if (mTabVisibleCount!=1){
this.scrollTo(
(position-(mTabVisibleCount-2))*tabWidth+(int)(tabWidth*offset)
,0);
}else{
this.scrollTo(position*tabWidth+(int)(tabWidth*offset),0);
}
}
//进行重绘
invalidate();
}
public int getScreenWidth() {
WindowManager wm = (WindowManager) getContext().getSystemService(Context.WINDOW_SERVICE);
DisplayMetrics outMetrics = new DisplayMetrics();
wm.getDefaultDisplay().getMetrics(outMetrics);
return outMetrics.widthPixels;
}
public void setTabItemTitles(List<String> titles) {
if (titles!=null&&titles.size()>0){
this.removeAllViews();
mTitles = titles;
for (String title:mTitles){
addView(generateTextView(title));
}
}
setTabItemClick();
}
/**
* 设置显示的tab的数量
* @param count
*/
public void setVisibleTabCount(int count){
mTabVisibleCount = count;
}
private View generateTextView(String title){
TextView tv = new TextView(getContext());
LinearLayout.LayoutParams lp = new LayoutParams(LayoutParams.MATCH_PARENT,LayoutParams.MATCH_PARENT);
lp.width = getScreenWidth()/mTabVisibleCount;
tv.setText(title);
tv.setGravity(Gravity.CENTER);
tv.setTextSize(TypedValue.COMPLEX_UNIT_SP,16);
tv.setTextColor(COLOR_TEXT_NORMAL);
tv.setLayoutParams(lp);
return tv;
}
private ViewPager mViewPager;
/**
* 设置关联的ViewPager
* @param viewPager
* @param pos
*/
public void setViewPager(ViewPager viewPager, final int pos){
mViewPager = viewPager;
mViewPager.addOnPageChangeListener(new ViewPager.OnPageChangeListener() {
//positionOffset是一个梯度值
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//tabWidth*positionOffset+positioin*tabWidth//移动时的偏移量
scroll(position, positionOffset);
if (mListener != null) {
mListener.onPageScrolled(position, positionOffset, positionOffsetPixels);
}
}
@Override
public void onPageSelected(int position) {
if (mListener != null) {
mListener.onPageSelected(position);
}
heightLightTextView(position);
}
@Override
public void onPageScrollStateChanged(int state) {
if (mListener != null) {
mListener.onPageScrollStateChanged(state);
}
}
});
mViewPager.setCurrentItem(pos);
heightLightTextView(pos);
}
public interface PageOnChangeListener{
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels);
public void onPageSelected(int position);
public void onPageScrollStateChanged(int state);
}
public PageOnChangeListener mListener;
public void setOnPageChangerListener(PageOnChangeListener listener){
this.mListener = listener;
}
/**
* 重置文本颜色
*/
private void resetTextViewColor(){
for (int i = 0; i < getChildCount(); i++) {
View view = getChildAt(i);
if (view instanceof TextView){
((TextView) view).setTextColor(COLOR_TEXT_NORMAL);
}
}
}
/**
* 高亮某个tab的文本
* @param pos
*/
private void heightLightTextView(int pos){
resetTextViewColor();
View view = getChildAt(pos);
if (view instanceof TextView){
((TextView) view).setTextColor(COLOR_TEXT_HIGHLIGHT);
}
}
/**
* 设置tab的点击事件
*/
private void setTabItemClick(){
int cCount = getChildCount();
for (int i = 0; i < cCount; i++) {
final int j = i;
View view = getChildAt(i);
view.setOnClickListener(new OnClickListener() {
@Override
public void onClick(View v) {
mViewPager.setCurrentItem(j);
}
});
}
}
}
2.用于装载的Fragment容器
package cq.cake.customview;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.Gravity;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
/**
* My Application -- cq.cake.customview
* Created by Small Cake on 2016/3/17 11:32.
*/
public class VpSimpleFragment extends Fragment {
private String mTilte;
private static final String BUNDLE_TITLE = "title";
@Nullable
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState) {
Bundle bundle = getArguments();
if (bundle!=null){
mTilte =bundle.getString(BUNDLE_TITLE);
}
TextView tv = new TextView(getActivity());
tv.setText(mTilte);
tv.setGravity(Gravity.CENTER);
return tv;
}
public static VpSimpleFragment newInstance(String title){
Bundle bundle = new Bundle();
bundle.putString(BUNDLE_TITLE,title);
VpSimpleFragment fragment = new VpSimpleFragment();
fragment.setArguments(bundle);
return fragment;
}
}
3.用于展示的MainActivity
package cq.cake.indicator;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentActivity;
import android.support.v4.app.FragmentPagerAdapter;
import android.support.v4.view.ViewPager;
import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;
import cq.cake.customview.ViewPagerIndicator;
import cq.cake.customview.VpSimpleFragment;
public class MainActivity extends FragmentActivity {
private ViewPager mViewPager;
private ViewPagerIndicator mIndicator;
private List<String> mTitles = Arrays.asList("短信1","收藏2","推荐3","短信4","收藏5","推荐6","短信7","收藏8","推荐9");
private List<VpSimpleFragment> mContents = new ArrayList<VpSimpleFragment>();
private FragmentPagerAdapter mAdapter;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main2);
initView();
initData();
mIndicator.setVisibleTabCount(3);
mIndicator.setTabItemTitles(mTitles);
mViewPager.setAdapter(mAdapter);
mIndicator.setViewPager(mViewPager,0);
mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
//positionOffset是一个梯度值
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) {
//tabWidth*positionOffset+positioin*tabWidth//移动时的偏移量
mIndicator.scroll(position, positionOffset);
}
@Override
public void onPageSelected(int position) {
}
@Override
public void onPageScrollStateChanged(int state) {
}
});
}
private void initData() {
for (String title:mTitles){
VpSimpleFragment fragment = VpSimpleFragment.newInstance(title);
mContents.add(fragment);
}
mAdapter = new FragmentPagerAdapter(getSupportFragmentManager()) {
@Override
public Fragment getItem(int position) {
return mContents.get(position);
}
@Override
public int getCount() {
return mContents.size();
}
};
}
private void initView() {
mViewPager = (ViewPager) findViewById(R.id.viewpager);
mIndicator = (ViewPagerIndicator) findViewById(R.id.indicator);
}
}
4.主页的layout
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:background="#ffffff"
xmlns:cake ="http://schemas.android.com/apk/res-auto"
tools:context="cq.cake.indicator.MainActivity">
<cq.cake.customview.ViewPagerIndicator
android:orientation="horizontal"
android:background="#383737"
android:id="@+id/indicator"
android:layout_width="match_parent"
cake:visible_tab_count="4"
android:layout_height="45dp">
</cq.cake.customview.ViewPagerIndicator>
<android.support.v4.view.ViewPager
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1"
android:id="@+id/viewpager"
/>
</LinearLayout>
代码中的注释已经写的够多了，如果还不明白的同学！可以下载源码看一下
源码地址：ViewPager滑动导航