方法listview使用

桃扇骨 2022-06-17 08:42 173阅读 0赞

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

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