Android ViewPager实现图片标题轮播和点击事件

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout
xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:layout_width="match_parent"
android:layout_height="match_parent"
tools:context="xyz.ncvt.viewpagerdemo.MainActivity"> <FrameLayout
android:layout_width="0dp"
android:layout_height="200dp" app:layout_constraintTop_toTopOf="parent"
app:layout_constraintLeft_toLeftOf="parent"
app:layout_constraintRight_toRightOf="parent"> <android.support.v4.view.ViewPager
android:id="@+id/viewPager"
android:layout_width="match_parent"
android:layout_height="match_parent" tools:layout_editor_absoluteY="0dp"
tools:layout_editor_absoluteX="8dp"/> <LinearLayout
android:weightSum="10"
android:background="#33000000"
android:orientation="horizontal"
android:layout_gravity="bottom"
android:gravity="center_vertical"
android:layout_width="match_parent"
android:layout_height="35dip">
<TextView
android:layout_weight="8"
android:id="@+id/tv_pager_title"
android:text="很长的标题。。。。。你懂我意思吧"
android:paddingLeft="8dip"
android:gravity="center_vertical"
android:textColor="@color/white"
android:layout_width="0dp" android:layout_height="35dip"/>
<!--用来动态添加轮播小点-->
<LinearLayout
android:id="@+id/lineLayout_dot"
android:layout_weight="2"
android:gravity="center|right"
android:layout_marginRight="5dp"
android:paddingLeft="3dp"
android:paddingRight="3dp"
android:orientation="horizontal"
android:layout_width="0dp" android:layout_height="match_parent">
</LinearLayout> </LinearLayout>
</FrameLayout></android.support.constraint.ConstraintLayout>

<vector android:height="5dp" android:viewportHeight="24.0"
android:viewportWidth="24.0" android:width="5dp" xmlns:android="http://schemas.android.com/apk/res/android">
<path android:fillColor="#fff" android:pathData="M12,12m-8,0a8,8 0,1 1,16 0a8,8 0,1 1,-16 0"/>
</vector>

<?xml version="1.0" encoding="utf-8"?>
<resources>
<item name="pager_image1" type="id" />
<item name="pager_image2" type="id" />
<item name="pager_image3" type="id" />
<item name="pager_image4" type="id" />
</resources>

import android.support.v4.view.PagerAdapter;
import android.support.v4.view.ViewPager;
import android.view.View;
import android.view.ViewGroup;
import android.widget.ImageView;import java.util.List;public class ViewPagerAdapter extends PagerAdapter {
private List<ImageView> images;
private ViewPager viewPager; /**
* 构造方法，传入图片列表和ViewPager实例
* @param images
* @param viewPager
*/ public ViewPagerAdapter(List<ImageView> images, ViewPager viewPager){
this.images = images;
this.viewPager = viewPager;
} @Override
public int getCount() {
return Integer.MAX_VALUE;//返回一个无限大的值，可以 无限循环
} /**
* 判断是否使用缓存, 如果返回的是true, 使用缓存. 不去调用instantiateItem方法创建一个新的对象
*/
@Override
public boolean isViewFromObject(View view, Object object) {
return view == object;
} /**
* 初始化一个条目
* @param container
* @param position 当前需要加载条目的索引
* @return
*/
@Override
public Object instantiateItem(ViewGroup container, int position) {
// 把position对应位置的ImageView添加到ViewPager中
ImageView iv = images.get(position % images.size());
viewPager.addView(iv);
// 把当前添加ImageView返回回去.
return iv;
}
/**
* 销毁一个条目
* position 就是当前需要被销毁的条目的索引
*/
@Override
public void destroyItem(ViewGroup container, int position, Object object) {
// 把ImageView从ViewPager中移除掉
viewPager.removeView(images.get(position % images.size())); }

public class MainActivity extends AppCompatActivity {
private ViewPager mViewPager;
private TextView mTvPagerTitle; private List<ImageView> mImageList;//轮播的图片集合
private String[] mImageTitles;//标题集合
private int previousPosition = 0;//前一个被选中的position
private List<View> mDots;//小点 private boolean isStop = false;//线程是否停止
private static int PAGER_TIOME = 5000;//间隔时间 // 在values文件假下创建了pager_image_ids.xml文件，并定义了4张轮播图对应的id，用于点击事件
private int[] imgae_ids = new int[]{R.id.pager_image1,R.id.pager_image2,R.id.pager_image3,R.id.pager_image4}; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
init();
} /**
* 第一步、初始化控件
*/
public void init() {
mViewPager = (ViewPager) findViewById(R.id.viewPager);
mTvPagerTitle = (TextView) findViewById(R.id.tv_pager_title);
initData();//初始化数据
initView();//初始化View，设置适配器
autoPlayView();//开启线程，自动播放
} /**
* 第二步、初始化数据（图片、标题、点击事件）
*/
public void initData() {
//初始化标题列表和图片
mImageTitles = new String[]{"这是一个好看的标题1","这是一个优美的标题2","这是一个快乐的标题3","这是一个开心的标题4"};
int[] imageRess = new int[]{R.drawable.ncvt_wifi_head,R.drawable.img1,R.drawable.img2,R.drawable.img3}; //添加图片到图片列表里
mImageList = new ArrayList<>();
ImageView iv;
for (int i = 0; i < mImageList.size(); i++) {
iv = new ImageView(this);
iv.setBackgroundResource(imageRess[i]);//设置图片
iv.setId(imgae_ids[i]);//顺便给图片设置id
iv.setOnClickListener(new pagerImageOnClick());//设置图片点击事件
mImageList.add(iv);
} //添加轮播点
LinearLayout linearLayoutDots = (LinearLayout) findViewById(R.id.lineLayout_dot);
mDots = addDots(linearLayoutDots,fromResToDrawable(this,R.drawable.ic_dot_normal),mImageList.size());//其中fromResToDrawable()方法是我自定义的，目的是将资源文件转成Drawable } //图片点击事件
private class pagerImageOnClick implements View.OnClickListener{ @Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.pager_image1:
Toast.makeText(MainActivity.this, "图片1被点击", Toast.LENGTH_SHORT).show();
break;
case R.id.pager_image2:
Toast.makeText(MainActivity.this, "图片2被点击", Toast.LENGTH_SHORT).show();
break;
case R.id.pager_image3:
Toast.makeText(MainActivity.this, "图片3被点击", Toast.LENGTH_SHORT).show();
break;
case R.id.pager_image4:
Toast.makeText(MainActivity.this, "图片4被点击", Toast.LENGTH_SHORT).show();
break;
}
}
}
/**
* 第三步、给PagerViw设置适配器，并实现自动轮播功能
*/
public void initView(){
ViewPagerAdapter viewPagerAdapter = new ViewPagerAdapter(mImageList, mViewPager);
mViewPager.setAdapter(viewPagerAdapter);
mViewPager.setOnPageChangeListener(new ViewPager.OnPageChangeListener() {
@Override
public void onPageScrolled(int position, float positionOffset, int positionOffsetPixels) { } @Override
public void onPageSelected(int position) {
//伪无限循环，滑到最后一张图片又从新进入第一张图片
int newPosition = position % mImageList.size();
// 把当前选中的点给切换了, 还有描述信息也切换
mTvPagerTitle.setText(mImageTitles[newPosition]);//图片下面设置显示文本
//设置轮播点
LinearLayout.LayoutParams newDotParams = (LinearLayout.LayoutParams) mDots.get(newPosition).getLayoutParams();
newDotParams.width = 24;
newDotParams.height = 24; LinearLayout.LayoutParams oldDotParams = (LinearLayout.LayoutParams) mDots.get(previousPosition).getLayoutParams();
oldDotParams.width = 16;
oldDotParams.height = 16; // 把当前的索引赋值给前一个索引变量, 方便下一次再切换.
previousPosition = newPosition; } @Override
public void onPageScrollStateChanged(int state) { }
});
setFirstLocation();
} /**
* 第四步：设置刚打开app时显示的图片和文字
*/
private void setFirstLocation() {
mTvPagerTitle.setText(mImageTitles[previousPosition]);
// 把ViewPager设置为默认选中Integer.MAX_VALUE / t2，从十几亿次开始轮播图片，达到无限循环目的;
int m = (Integer.MAX_VALUE / 2) % mImageList.size();
int currentPosition = Integer.MAX_VALUE / 2 - m;
mViewPager.setCurrentItem(currentPosition);
} /**
* 第五步: 设置自动播放,每隔PAGER_TIOME秒换一张图片
*/
private void autoPlayView() {
//自动播放图片
new Thread(new Runnable() {
@Override
public void run() {
while (!isStop){
runOnUiThread(new Runnable() {
@Override
public void run() {
mViewPager.setCurrentItem(mViewPager.getCurrentItem() + 1);
}
});
SystemClock.sleep(PAGER_TIOME);
}
}
}).start();
} /**
* 资源图片转Drawable
* @param context
* @param resId
* @return
*/
public Drawable fromResToDrawable(Context context, int resId) {
return context.getResources().getDrawable(resId);
} /**
* 动态添加一个点
* @param linearLayout 添加到LinearLayout布局
* @param backgount 设置
* @return
*/
public int addDot(final LinearLayout linearLayout, Drawable backgount) {
final View dot = new View(this);
LinearLayout.LayoutParams dotParams = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT);
dotParams.width = 16;
dotParams.height = 16;
dotParams.setMargins(4,0,4,0);
dot.setLayoutParams(dotParams);
dot.setBackground(backgount);
dot.setId(View.generateViewId());
linearLayout.addView(dot);
return dot.getId();
} /**
* 添加多个轮播小点到横向线性布局
* @param linearLayout
* @param backgount
* @param number
* @return
*/
public List<View> addDots(final LinearLayout linearLayout, Drawable backgount, int number){
List<View> dots = new ArrayList<>();
for (int i = 0; i < number; i++) {
int dotId = addDot(linearLayout,backgount);
dots.add(findViewById(dotId));
}
return dots;
}