Android学习【5】自定义ArrayAdapter

通过ArrayList显示数据首先要绑定一个ArrayAdapter(适配器)然后将数据传入，详细效果如下：

        final ArrayAdapter<String> aa;
        adapter = new ArrayAdapter<String>(this,android.R.layout.simple_list_item_1,myitems);
        myListView.setAdapter(adapter );

在这里R.layout.simple_list_item_1是系统默认布局，myitems为一个String数组，存储需要进行表达的数据。

下面来聊聊自定义适配器。

1.实例化自定义适配器
2.重写getView方法用于数据映射（系统将通过此函数绘制每行数据）。
    getView()の参数说明（position表示第几行，convertView为自定义item布局(通过LayoutInflater提取出来的)）
3.获取组件并进行设置。

源码如下:

activity_main.xml

<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:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin" tools:context=".MainActivity"
    android:orientation="vertical">

    <EditText
        android:id="@+id/myEditText"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:hint="请输入"
        android:contentDescription="输入文本"/>

    <ListView
        android:id="@+id/myListView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

</LinearLayout>

myitem.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="horizontal">
<ImageView
    android:id="@+id/item_thumbnail"
    android:layout_height="48dip"
    android:layout_width="48dip"
    />
<TextView
    android:id="@+id/item_file_name"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceLarge"
    android:minHeight="?android:attr/listPreferredItemHeight"
    android:gravity="center_vertical"
    android:paddingLeft="5dip"
    />

<TextView
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:textAppearance="?android:attr/textAppearanceMedium"
    android:text=""
    android:id="@+id/textView2" />
</LinearLayout>

MainActivity.java

package com.android.simonnear.mytest;

import android.app.Activity;
import android.os.Bundle;
import android.view.KeyEvent;
import android.view.View;
import android.widget.EditText;
import android.widget.ListView;

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


public class MainActivity extends Activity {

    private ListView myListView;
    private EditText myEditText;
    List<Book> fileList = new ArrayList<Book>();

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        myListView = (ListView)findViewById(R.id.myListView);
        myEditText = (EditText)findViewById(R.id.myEditText);

        Book b = new Book();
        b.setName("Demo1");
        b.setYear("1999");
        fileList.add(b);
        b = new Book();
        b.setName("Demo2");
        b.setYear("2000");
        fileList.add(b);
        final TestAdapter adapter = new TestAdapter(MainActivity.this,
                R.layout.myitem,
                fileList);
        myListView.setAdapter(adapter);


        myEditText.setOnKeyListener(new View.OnKeyListener() {
            @Override
            public boolean onKey(View v, int keyCode, KeyEvent event) {
                if(event.getAction()==KeyEvent.ACTION_DOWN)
                    if((keyCode==KeyEvent.KEYCODE_DPAD_CENTER)||(keyCode==KeyEvent.KEYCODE_ENTER)) {
                        Book b = new Book();
                        b.setName(myEditText.getText().toString());
                        b.setYear("2009");
                        fileList.add(0,b);
                        adapter.notifyDataSetChanged();
                        myEditText.setText("");
                        return true;
                    }
                return false;
            }
        });
    }
}

Book.java

package com.android.simonnear.mytest;

/**
 * Created by Simonnear on 2015/9/25.
 */
public class Book {
    private String Name,Year;

    public String getName() {
        return Name;
    }

    public void setName(String name) {
        Name = name;
    }

    public String getYear() {
        return Year;
    }

    public void setYear(String year) {
        Year = year;
    }
}

TestAdapter.java

package com.android.simonnear.mytest;

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.LinearLayout;
import android.widget.TextView;

import java.util.List;

/**
 * Created by Simonnear on 2015/9/25.
 */
public class TestAdapter extends ArrayAdapter<Book> {

    private int resource;

    public TestAdapter(Context context, int resourceId, List<Book> objects) {
        super(context, resourceId, objects);
        // 记录下来稍后使用
        resource = resourceId;
    }

    public View getView(int position, View convertView, ViewGroup parent) {
        LinearLayout imageListView;
        // 获取数据
        Book b = getItem(position);
        String name = b.getName();
        String year = b.getYear();

        if(convertView == null) {
            imageListView = new LinearLayout(getContext());
            LayoutInflater inflater = (LayoutInflater)getContext().getSystemService(Context.LAYOUT_INFLATER_SERVICE);
            inflater.inflate(resource, imageListView, true);//把image_item.xml布局解析到LinearLayout里面
        } else {
            imageListView = (LinearLayout)convertView;
        }

        // 获取控件,填充数据
        ImageView imageView = (ImageView) imageListView.findViewById(R.id.item_thumbnail);
        TextView textView = (TextView) imageListView.findViewById(R.id.item_file_name);
        TextView textView2 = (TextView) imageListView.findViewById(R.id.textView2);
        textView.setText(name);
        textView2.setText(year);
        imageView.setBackgroundResource(R.mipmap.ic_launcher);

        return imageListView;
    }
}