最近学习安卓,学了一段时间,感觉很乱,现在开始把每一个功能单独集合一下
这篇博文介绍listview,完整代码很适合我这样的新手看,
1、首先是activity_main.xml里面添加ListView控件
<ListView android:id="@+id/list_book" android:layout_width="fill_parent" android:layout_weight="1" android:layout_height="0dp"/>这里还需要一个装item的视图文件list_one.xml
<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="horizontal" android:padding="10dp"> <TextView android:id="@+id/txt_bname" android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="《第一行代码Android》" android:textColor="#F3684A" android:textSize="18sp" /> <TextView android:id="@+id/txt_bauthor" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_marginLeft="20dp" android:text="郭霖" android:textColor="#44BDED" android:textSize="18sp" /> </LinearLayout>
然后编写一个类表示item的类型;这里示例为Book.java
package jay.com.listviewdemo4; /** * Created by Jay on 2015/9/22 0022. */ public class Book { private String bName; private String bAuthor; public Book() { } public Book(String bName, String bAuthor) { this.bName = bName; this.bAuthor = bAuthor; } public String getbName() { return bName; } public String getbAuthor() { return bAuthor; } public void setbName(String bName) { this.bName = bName; } public void setbAuthor(String bAuthor) { this.bAuthor = bAuthor; } }然后编写一个自己的Adapter(适配器的意思)类命名为MyAdapter.java
package jay.com.listviewdemo4; import android.content.Context; import android.util.SparseArray; import android.view.LayoutInflater; import android.view.View; import android.view.ViewGroup; import android.widget.BaseAdapter; import android.widget.ImageView; import android.widget.TextView; import java.util.ArrayList; /** * Created by Jay on 2015/9/22 0022. */ public abstract class MyAdapter<T> extends BaseAdapter { private ArrayList<T> mData; private int mLayoutRes; //布局id public MyAdapter() { } public MyAdapter(ArrayList<T> mData, int mLayoutRes) { this.mData = mData; this.mLayoutRes = mLayoutRes; } @Override public int getCount() { return mData != null ? mData.size() : 0; } @Override public T getItem(int position) { return mData.get(position); } @Override public long getItemId(int position) { return position; } @Override public View getView(int position, View convertView, ViewGroup parent) { ViewHolder holder = ViewHolder.bind(parent.getContext(), convertView, parent, mLayoutRes , position); bindView(holder, getItem(position)); return holder.getItemView(); } public abstract void bindView(ViewHolder holder, T obj); //添加一个元素 public void add(T data) { if (mData == null) { mData = new ArrayList<>(); } mData.add(data); notifyDataSetChanged(); } //往特定位置,添加一个元素 public void add(int position, T data) { if (mData == null) { mData = new ArrayList<>(); } mData.add(position, data); notifyDataSetChanged(); } public void remove(T data) { if (mData != null) { mData.remove(data); } notifyDataSetChanged(); } public void remove(int position) { if (mData != null) { mData.remove(position); } notifyDataSetChanged(); } public void clear() { if (mData != null) { mData.clear(); } notifyDataSetChanged(); } public static class ViewHolder { private SparseArray<View> mViews; //存储ListView 的 item中的View private View item; //存放convertView private int position; //游标 private Context context; //Context上下文 //构造方法,完成相关初始化 private ViewHolder(Context context, ViewGroup parent, int layoutRes) { mViews = new SparseArray<>(); this.context = context; View convertView = LayoutInflater.from(context).inflate(layoutRes, parent, false); convertView.setTag(this); item = convertView; } //绑定ViewHolder与item public static ViewHolder bind(Context context, View convertView, ViewGroup parent, int layoutRes, int position) { ViewHolder holder; if (convertView == null) { holder = new ViewHolder(context, parent, layoutRes); } else { holder = (ViewHolder) convertView.getTag(); holder.item = convertView; } holder.position = position; return holder; } @SuppressWarnings("unchecked") public <T extends View> T getView(int id) { T t = (T) mViews.get(id); if (t == null) { t = (T) item.findViewById(id); mViews.put(id, t); } return t; } /** * 获取当前条目 */ public View getItemView() { return item; } /** * 获取条目位置 */ public int getItemPosition() { return position; } /** * 设置文字 */ public ViewHolder setText(int id, CharSequence text) { View view = getView(id); if (view instanceof TextView) { ((TextView) view).setText(text); } return this; } /** * 设置图片 */ public ViewHolder setImageResource(int id, int drawableRes) { View view = getView(id); if (view instanceof ImageView) { ((ImageView) view).setImageResource(drawableRes); } else { view.setBackgroundResource(drawableRes); } return this; } /** * 设置点击监听 */ public ViewHolder setOnClickListener(int id, View.OnClickListener listener) { getView(id).setOnClickListener(listener); return this; } /** * 设置可见 */ public ViewHolder setVisibility(int id, int visible) { getView(id).setVisibility(visible); return this; } /** * 设置标签 */ public ViewHolder setTag(int id, Object obj) { getView(id).setTag(obj); return this; } //其他方法可自行扩展 } }然后是MainActivity.java
package jay.com.listviewdemo4; import android.content.Context; import android.os.Bundle; import android.support.v7.app.AppCompatActivity; import android.widget.ListView; import java.util.ArrayList; import java.util.List; public class MainActivity extends AppCompatActivity { private Context mContext; private ListView list_book; private ListView list_app; private MyAdapter<App> myAdapter1 = null; private MyAdapter<Book> myAdapter2 = null; private List<App> mData1 = null; private List<Book> mData2 = null; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); mContext = MainActivity.this; init(); } private void init() { list_book = (ListView) findViewById(R.id.list_book); list_app = (ListView) findViewById(R.id.list_app); //数据初始化 mData1 = new ArrayList<App>(); mData1.add(new App(R.mipmap.iv_icon_baidu,"百度1")); mData1.add(new App(R.mipmap.iv_icon_douban,"豆瓣1")); mData1.add(new App(R.mipmap.iv_icon_zhifubao,"支付宝1")); mData2 = new ArrayList<Book>(); mData2.add(new Book("《第一行代码Android》","郭霖")); mData2.add(new Book("《Android群英传》","徐宜生")); mData2.add(new Book("《Android开发艺术探索》","任玉刚")); //Adapter初始化 myAdapter1 = new MyAdapter<App>((ArrayList)mData1,R.layout.item_one) { @Override public void bindView(ViewHolder holder, App obj) { holder.setImageResource(R.id.img_icon,obj.getaIcon()); holder.setText(R.id.txt_aname,obj.getaName()); } }; myAdapter2 = new MyAdapter<Book>((ArrayList)mData2,R.layout.item_two) { @Override public void bindView(ViewHolder holder, Book obj) { holder.setText(R.id.txt_bname,obj.getbName()); holder.setText(R.id.txt_bauthor,obj.getbAuthor()); } }; //ListView设置下Adapter: list_book.setAdapter(myAdapter2); list_app.setAdapter(myAdapter1); } }使用时只需要更换ID就行了