安卓-ListView基本使用

今天的目标是使用ListView控件完成一个布局，左边一个图标，右边分为上线两部分：标题和内容;

ListView在使用时要考虑内存优化，就是使用ViewHolder(自己定义的一个内部类，存储布局中的控件的索引)

适配器使用继承自ArrayAdapter的适配器，也可以继承自BaseAdapter(要多写几个方法)

目前虽然还有公司在使用，但是后面大家陆续都会转向RecyclerView,RecyclerView的功能很强大，已完成涵盖了ListView的功能，且可以解决行点击和行中的项点击的冲突。

主Activity和对应的布局文件如下:

activity_list_view_base_activity.xml

<?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">    <ListView        android:id="@+id/listView"        android:layout_width="match_parent"        android:layout_height="match_parent">    </ListView></LinearLayout>

ListViewBaseActivity.java

import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.AdapterView;import android.widget.ListView;import android.widget.Toast;import com.mobile.cdtx.blog.R;import com.mobile.cdtx.blog.main.adapter.ListViewAdapter;import com.mobile.cdtx.blog.main.data.ListData;import java.util.ArrayList;import java.util.List;public class ListViewBaseActivity extends AppCompatActivity {    private List<ListData> dataList = new ArrayList<ListData>();    private ListView listView;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_list_view_base_acitiy);        initData();        ListViewAdapter listViewAdapter = new ListViewAdapter(ListViewBaseActivity.this,R.layout.list_item,dataList);        listView = (ListView) findViewById(R.id.listView);        listView.setAdapter(listViewAdapter);        listView.setOnItemClickListener(new AdapterView.OnItemClickListener() {            @Override            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {                Toast.makeText(ListViewBaseActivity.this,"当前选中第"+position+"行",Toast.LENGTH_SHORT).show();            }        });    }    //初始化数据    private void initData(){        for (int i = 0; i < 100; i++) {            ListData data = new ListData("name"+i, "内容"+i,R.mipmap.ic_launcher);            dataList.add(data);        }    }}

自定义的适配器ListViewAdapter.Java

import android.content.Context;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.ArrayAdapter;import android.widget.ImageView;import android.widget.TextView;import com.mobile.cdtx.blog.R;import com.mobile.cdtx.blog.main.data.ListData;import java.util.List;/** * Created by wangwentao on 2017/2/13. */public class ListViewAdapter extends ArrayAdapter<ListData> {    private int resourceId;    public ListViewAdapter(Context context, int textViewResourceId,                        List<ListData> objects) {        super(context, textViewResourceId, objects);        resourceId = textViewResourceId;    }    @Override    public View getView(int position, View convertView, ViewGroup parent) {        ListData data = getItem(position); // 获取当前项的Fruit实例        View view;        ViewHolder viewHolder;        if (convertView == null) {            view = LayoutInflater.from(getContext()).inflate(resourceId, parent, false);            viewHolder = new ViewHolder();            viewHolder.dataImage = (ImageView) view.findViewById (R.id.img);            viewHolder.dataName = (TextView) view.findViewById (R.id.tvTitle);            viewHolder.dataContent = (TextView) view.findViewById (R.id.tvContent);            view.setTag(viewHolder); // 将ViewHolder存储在View中        } else {            view = convertView;            viewHolder = (ViewHolder) view.getTag(); // 重新获取ViewHolder        }        viewHolder.dataImage.setImageResource(data.getImageId());        viewHolder.dataName.setText(data.getName());        return view;    }    class ViewHolder {        ImageView dataImage;        TextView dataName;        TextView dataContent;    }}

每行展示的数据的实体类ListData.java

/** * Created by wangwentao on 2017/2/13. */public class ListData {    private String name;    private String content;    private int imageId;    public ListData(String name, String content,int imageId) {        this.name = name;        this.imageId = imageId;        this.content = content;    }    public String getName() {        return name;    }    public int getImageId() {        return imageId;    }    public String getContent(){        return content;    }}

显示每行布局的xml文件 list_item.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="wrap_content"              android:orientation="horizontal">    <ImageView        android:id="@+id/img"        android:layout_margin="10dp"        android:layout_width="40dp"        android:layout_height="40dp"        android:layout_gravity="center_vertical"        android:src="@mipmap/ic_launcher"         />     <LinearLayout         android:layout_gravity="center_vertical"         android:layout_width="wrap_content"         android:layout_height="wrap_content"         android:orientation="vertical">         <TextView             android:id="@+id/tvTitle"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:textColor="#333333"             android:textSize="14sp"             android:text="HellO"/>         <TextView             android:id="@+id/tvContent"             android:layout_width="wrap_content"             android:layout_height="wrap_content"             android:textColor="#999999"             android:textSize="12sp"             android:text="World"/>     </LinearLayout></LinearLayout>

效果图就不贴了，每次图都显示不出来