ViewPager+Fragment+ListView打造新闻列表
今天接触到了Fragment碎片，也是现在编写APP的主流道具。那么今天我用ViewPager、Fragment和ListView做了一个新闻列表，分享给大家。效果图里上方的指示器是用了第三方工具PagerSlidingTabStrip完成的，非常好用！省去了好多我之前写的监听事件。
首先，我们建一个Activity，然后在新建的Activity的layout中添加两个控件:
前者为第三方工具PagerSlidingTabStrip，后者V4包的ViewPager。
然后我们建一个空的Fragment。记住，建Fragment的时候先别勾选下面的两个对号，不然的话对于初学者显得有些乱。
这Fragment自带的layout中，我们放一个ListView控件。
public class News implements Serializable{
private String title;
private String pubDate;
private int img;
private int img1;
private int img2;
private int img3;
public News(String title, String pubDate, int img, int img1, int img2, int img3) {
this.title = title;
this.pubDate = pubDate;
this.img = img;
this.img1 = img1;
this.img2 = img2;
this.img3 = img3;
}
public String getTitle() {
return title;
}
public void setTitle(String title) {
this.title = title;
}
public String getPubDate() {
return pubDate;
}
public void setPubDate(String pubDate) {
this.pubDate = pubDate;
}
public int getImg() {
return img;
}
public void setImg(int img) {
this.img = img;
}
public int getImg1() {
return img1;
}
public void setImg1(int img1) {
this.img1 = img1;
}
public int getImg2() {
return img2;
}
public void setImg2(int img2) {
this.img2 = img2;
}
public int getImg3() {
return img3;
}
public void setImg3(int img3) {
this.img3 = img3;
}
}
match_parent"
android:id="@+id/tv"
android:gravity="center"
android:textColor="#408fde"
android:textSize="30sp"/> 这里我们需要两个适配器，一个是FragmentViewPager的，一个是FragmentListView的。下面直接给出。
public class MyFragmentViewAdapter extends FragmentPagerAdapter {
private List list;
private List title;
private Context context;
public MyFragmentViewAdapter(FragmentManager fm, List list,List title) {
super(fm);
this.title = title;
this.list = list;
}
@Override
public Fragment getItem(int position) {
return list.get(position);
}
@Override
public int getCount() {
return list.size();
}
@Override
public CharSequence getPageTitle(int position) {
return title.get(position);
}
} public class MyListViewAdapter extends BaseAdapter {
private Context context;
private List list;
public MyListViewAdapter(Context context, List list) {
this.context = context;
this.list = list;
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int i) {
return list.get(i);
}
@Override
public long getItemId(int i) {
return 0;
}
@Override
public View getView(int i, View view, ViewGroup viewGroup) {
ViewHolder vh;
if(view==null){
vh = new ViewHolder();
view = LayoutInflater.from(context).inflate(R.layout.list_simple_layout,null);
vh.img = (ImageView) view.findViewById(R.id.iv);
vh.title = (TextView) view.findViewById(R.id.tv);
view.setTag(vh);
}else {
vh = (ViewHolder) view.getTag();
}
view.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Intent intent = new Intent(context, Main2Activity.class);
context.startActivity(intent);
}
});
vh.img.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View view) {
Toast.makeText(context,"点击图片",Toast.LENGTH_SHORT).show();
}
});
News news = list.get(i);
vh.title.setText(news.getTitle());
vh.img.setImageResource(news.getImg());
return view;
}
public class ViewHolder{
TextView title;
ImageView img;
}
} 首先，一开始的Activity。
public class ToDayNewsActivity extends AppCompatActivity {
//建两个全局变量，等下用它们获取layout里面的两个控件
private ViewPager vp;
private PagerSlidingTabStrip pst;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_to_day_news);
//这里我改了一下Toolbar的样式，和文章主题无关紧要
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
//用上面的两个全局变量find到控件
vp = (ViewPager) findViewById(R.id.vp);
pst = (PagerSlidingTabStrip) findViewById(R.id.pst);
//建一个List，泛型设为Fragment，用来存放Fragment
List list = new ArrayList<>();
//建一个存放字符串的List，这里是为了用第三方工具PagerSlidingTabStrip而弄的，因为要往里面穿一些参数。
//最后呈现的是上方的可点击指示器
List title = new ArrayList<>();
title.add("体育");
title.add("娱乐");
title.add("奥运");
title.add("财经");
title.add("国际");
//来个循环，我这里弄了五次，建了5个ListViewFragment，并且往ListViewFragment里捆绑了一些整数，用于判断
//并区分多种新闻内容
for(int i = 1;i<=5;i++){
Fragment fragment = new ListViewFragment();
Bundle bundle = new Bundle();
bundle.putInt("arg",i);
fragment.setArguments(bundle);
list.add(fragment);
}
//将存放了Fragment的列表和指示器的参量加载到适配器中，然后将适配器变量加载到ViewPager中
//最后将ViewPager放到布局的PagerSlidingTabStrip第三方控件里
MyFragmentViewAdapter ma = new MyFragmentViewAdapter(getSupportFragmentManager(),list,title);
vp.setAdapter(ma);
pst.setViewPager(vp);
}
} public class ListViewFragment extends Fragment {
public ListViewFragment() {
// Required empty public constructor
}
@Override
public View onCreateView(LayoutInflater inflater, ViewGroup container,
Bundle savedInstanceState) {
// Inflate the layout for this fragment
return inflater.inflate(R.layout.fragment_list_view, container, false);
}
@Override
public void onActivityCreated(@Nullable Bundle savedInstanceState) {
super.onActivityCreated(savedInstanceState);
//这里建一个List用来存放News新闻类
final List list = new ArrayList<>();
//创建了个ListView变量用来获取layout中的ListView
ListView lv1 = (ListView) getView().findViewById(R.id.lv1);
//建一个适配的变量，将上下文和list加载到ListVIew的适配器中，然后放到适配器变量里
MyListViewAdapter ma = new MyListViewAdapter(getActivity(),list);
//将适配器变量的内容加载到List里(也就是把那一堆新闻都放了进去)
lv1.setAdapter(ma);
//获取Activity里传过来的捆绑数据
Bundle bundle = getArguments();
//用来判断是那一中新闻
if(bundle != null){
int arg = bundle.getInt("arg");
switch (arg){
case 1:
for(int i = 1;i<20;i++){
list.add(new News("暴走大事件","刚刚",R.mipmap.mei02,
R.mipmap.mei02,R.mipmap.mei02,R.mipmap.mei05));
}
ma.notifyDataSetChanged();
break;
case 2:
for(int i = 1;i<20;i++){
list.add(new News("暴走大事件","刚刚",R.mipmap.mei02,
R.mipmap.mei02,R.mipmap.mei02,R.mipmap.mei05));
}
ma.notifyDataSetChanged();
break;
case 3:
for(int i = 1;i<20;i++){
list.add(new News("推理要在晚饭后","昨天",R.mipmap.mei02,
R.mipmap.mei02,R.mipmap.mei02,R.mipmap.mei05));
}
ma.notifyDataSetChanged();
break;
case 4:
for(int i = 1;i<20;i++){
list.add(new News("嘿嘿嘿~","晚上",R.mipmap.mei02,
R.mipmap.mei02,R.mipmap.mei02,R.mipmap.mei05));
}
ma.notifyDataSetChanged();
break;
case 5:
for(int i = 1;i<20;i++){
list.add(new News("- -、守望","凌晨2点",R.mipmap.mei02,
R.mipmap.mei02,R.mipmap.mei02,R.mipmap.mei05));
}
ma.notifyDataSetChanged();
break;
default:break;
}
}
//这里用到了监听事件，目的是点击新闻列表中的新闻后跳转到完整的新闻界面
lv1.setOnItemClickListener(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView adapterView, View view, int i, long l) {
News news = list.get(i);
Toast.makeText(getActivity(),news.getTitle(),Toast.LENGTH_SHORT).show();
Intent intent = new Intent(getActivity(), IntentActivity.class);
intent.putExtra("obj",news);
Bundle bundle1 = new Bundle();
bundle1.putString("arg1","新闻详情");
intent.putExtra("bundle",bundle1);
startActivity(intent);
}
});
}
}
最后是跳转的Activiry的代码。
public class IntentActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_intent);
TextView tv = (TextView) findViewById(R.id.tv);
ImageView iv = (ImageView) findViewById(R.id.iv);
Intent intent = getIntent();
News news = (News) intent.getSerializableExtra("obj");
Bundle bundle = intent.getBundleExtra("bundle");
String arg = bundle.getString("arg1");
StringBuilder sbld = new StringBuilder();
sbld.append(arg+"\n");
sbld.append(news.getTitle()+"\n");
sbld.append(news.getPubDate()+"\n");
tv.setText(sbld.toString());
iv.setImageResource(news.getImg());
}
}预览图如下:
