android基础---->ListView的使用

简单说明

• ListView在android程序中比较常用，在此做一下简单的总结
• 内容：自定义ListView, 自定义Adapter，ListView滚动事件的应用！

 

项目结构如下图

 

ListView的使用：

• 建立一个listView的布局文件，命名为：item_layout.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:paddingLeft="16dp"
    android:paddingTop="16dp">
    <LinearLayout
        android:gravity="center_vertical"
        android:orientation="horizontal"
        android:layout_width="match_parent"
        android:layout_height="60dp">
        <ImageView
            android:id="@+id/imageView"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:src="@mipmap/ic_launcher" />
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="16dp"
            android:orientation="vertical">
            <TextView
                android:id="@+id/textView1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:text="Hello World" />
            <TextView
                android:id="@+id/textView2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content"
                android:layout_marginTop="10dp"
                android:text="Hello World" />
        </LinearLayout>
        <Button
            android:id="@+id/button"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_marginLeft="20dp"
            android:text="Button" />
    </LinearLayout>
</LinearLayout>

大致视图如下

 

• 创建一个自定义ListView的布局文件：activity_main.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:paddingBottom="@dimen/activity_vertical_margin"
    android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    tools:context="com.example.linux.listviewscrolltest.MainActivity">

    <com.example.linux.listviewscrolltest.linux.CustomListView
        android:id="@+id/listView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content">
    </com.example.linux.listviewscrolltest.linux.CustomListView>
</LinearLayout>

• 建立一个Entity，命名为：PersonEntiry.java，用于显示

package com.example.linux.listviewscrolltest.linux;

/**
 * Created by Linux on 2016/3/13.
 */
public class PersonEntiry {
    private int imageId;
    private String username;
    private String password;
    private String button;

    public int getImageId() {
        return imageId;
    }

    public void setImageId(int imageId) {
        this.imageId = imageId;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getButton() {
        return button;
    }

    public void setButton(String button) {
        this.button = button;
    }
}

• 建立一个Holder，命名为：PersonViewHolder.java，对应于布局文件中的四个组件

package com.example.linux.listviewscrolltest.linux;

import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

/**
 * Created by Linux on 2016/3/13.
 */
public class PersonViewHolder {
    ImageView imageView;

    TextView textView1;

    TextView textView2;

    Button button;
}

• 创建一个ListView的适配器，命名为PersonAdapter.java, 重写父类的四个方法：

package com.example.linux.listviewscrolltest.linux;

import android.content.Context;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import com.example.linux.listviewscrolltest.R;

import java.util.List;

/**
 * Created by 胡红翔 on 2016/3/13.
 * function: 自定义ListView的适配器
 *
 */
public class PersonAdapter extends BaseAdapter {
    List<PersonEntiry> personEntiries;
    LayoutInflater inflater;

    public PersonAdapter(Context context, List<PersonEntiry> personEntiries) {
        this.personEntiries = personEntiries;
        this.inflater = LayoutInflater.from(context);
    }

    @Override
    public int getCount() {
        return personEntiries.size();
    }

    @Override
    public Object getItem(int position) {
        return personEntiries.get(position);
    }

    @Override
    public long getItemId(int position) {
        return position;
    }

    @Override
    public View getView(int position, View convertView, ViewGroup parent) {
        PersonEntiry entity = personEntiries.get(position);
        PersonViewHolder holder;
        if (convertView == null) {
            holder = new PersonViewHolder();
            convertView = inflater.inflate(R.layout.item_layout, null);
            holder.imageView = (ImageView) convertView.findViewById(R.id.imageView);
            holder.textView1 = (TextView) convertView.findViewById(R.id.textView1);
            holder.textView2 = (TextView) convertView.findViewById(R.id.textView2);
            holder.button = (Button) convertView.findViewById(R.id.button);
            convertView.setTag(holder);
        } else {
            holder = (PersonViewHolder) convertView.getTag();
        }
        holder.imageView.setImageResource(entity.getImageId());
        holder.textView1.setText(entity.getUsername());
        holder.textView2.setText(entity.getPassword());
        holder.button.setText(entity.getButton());
        return convertView;
    }
}

•  创建一个自定义的ListView:CustomListView，添加滚动事件：

package com.example.linux.listviewscrolltest.linux;

import android.content.Context;
import android.util.AttributeSet;
import android.util.Log;
import android.widget.AbsListView;
import android.widget.ListView;

/**
 * Created by Linux on 2016/3/13.
 * function: 自定义的ListView
 */
public class CustomListView extends ListView implements AbsListView.OnScrollListener {
    private static final String TAG = "MainActivity";

    public CustomListView(Context context) {
        super(context);
        setOnScrollListener(this);
    }

    public CustomListView(Context context, AttributeSet attrs) {
        super(context, attrs);
        setOnScrollListener(this);
    }

    public CustomListView(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
        setOnScrollListener(this);
    }

    @Override
    public void onScrollStateChanged(AbsListView view, int scrollState) {
        // view应该就是可见的View的集合
        Log.i(TAG, "state change: " + scrollState + ", view size: " + view.getChildCount());
    }

    @Override
    public void onScroll(AbsListView view, int firstVisibleItem, int visibleItemCount, int totalItemCount) {
        Log.i(TAG, "on scroll: " + firstVisibleItem + ", visible: " + visibleItemCount + " , " + totalItemCount);
    }
}

•  最后在MainActivity中使用自定义的ListView：

package com.example.linux.listviewscrolltest;

import android.os.Bundle;
import android.support.v7.app.AppCompatActivity;

import com.example.linux.listviewscrolltest.linux.CustomListView;
import com.example.linux.listviewscrolltest.linux.PersonAdapter;
import com.example.linux.listviewscrolltest.linux.PersonEntiry;

import java.util.ArrayList;
import java.util.List;

public class MainActivity extends AppCompatActivity {

    private static final String TAG = "MainActivity";
    private CustomListView listView;
    private PersonAdapter personAdapter;
    private List<PersonEntiry> personEntiries = new ArrayList<>();
    private PersonEntiry entity;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        listView = (CustomListView) findViewById(R.id.listView);

        setData();
        initListView();
    }

    // 增加数据
    private void setData() {
        for (int i = 0; i < 10; i++) {
            entity = new PersonEntiry();
            entity.setImageId(R.mipmap.ic_launcher);
            entity.setUsername("linux: " + i);
            entity.setPassword("huhx: " + i);
            entity.setButton("刘力: " + i);
            personEntiries.add(entity);
        }
    }

    // 生成ListView
    private void initListView() {
        personAdapter = new PersonAdapter(this, personEntiries);
        listView.setAdapter(personAdapter);
    }
}

•  为测试方便，附上AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
    package="com.example.linux.listviewscrolltest">

    <application
        android:allowBackup="true"
        android:icon="@mipmap/ic_launcher"
        android:label="@string/app_name"
        android:supportsRtl="true"
        android:theme="@style/AppTheme">
        <activity android:name=".MainActivity">
            <intent-filter>
                <action android:name="android.intent.action.MAIN" />

                <category android:name="android.intent.category.LAUNCHER" />
            </intent-filter>
        </activity>
    </application>

</manifest>

 

实现过程

ListView中比较重要的几个要素：

• 数据：
• 适配器adapter：
• listview：

然后，根据适配器的种类，我们可以把listview分成三种，有ArrayAdapter，SimpleAdapter和SimpleCursorAdapter，而最后一种是专门与数据库连接用的。

 

链接：