Adapter与ListView的简单应用（下）Android应用界面开发

public class ArrayAdapter<T> extends BaseAdapter implements Filterable, ThemedSpinnerAdapter {...}

 public ArrayAdapter(Context context, int resource, List<T> objects)

public class Data {
 private String Text; //需要显示的文字
 private int ImageId; //需要显示的图片资源编号

 public Data(String text, int imageId) {
 Text = text;
 ImageId = imageId;
 }
 public String getText() {
 return Text;
 }
 public int getImageId() {
 return ImageId;
 }
}

public class DataAdapter extends ArrayAdapter<Data> {
 int mResourceId;

 public DataAdapter(Context context, int resource, List<Data> objects) {
 super(context, resource, objects); //调用ArrayAdapter的构造方法
 mResourceId = resource; //获取list的布局文件
 }

 @Override
 public View getView(int position, View convertView, ViewGroup parent) {
 //重写getView方法
 Data mData = getItem(position);
 //获取此Data
 ViewHolder mViewHolder;
 if (convertView == null){
 //如果view未被创建过，且缓存为空
 mViewHolder = new ViewHolder();
 convertView= LayoutInflater.from(getContext()).inflate(mResourceId,null);
 //此时，将mResourceId转换成了View类
 /*其实LayoutInflater.from(Context context)方法，就是包含下列参数的静态方法
 /LayoutInflater LayoutInflater =(LayoutInflater) context.getSystemService(Context.LAYOUT_INFLATER_SERVICE);
 获得了系统的布局解析服务*/
 //inflate的第一个参数是布局文件Id，第二个ViewGroup对象，在创建单独的view的时候，只需要填null

 mViewHolder.textView = (TextView)convertView.findViewById(R.id.textView);
 mViewHolder.image = (ImageView) convertView.findViewById(R.id.image);
 //通过convertView找到其中的控件

 convertView.setTag(mViewHolder);
 //将ViewHolder类存储到已经实例化的convertView中
 }else {
 //如果convertView有值
 mViewHolder = (ViewHolder) convertView.getTag();
 //从convertView中拿到ViewHolder类，从而可以使用其中的对象
 }
 mViewHolder.textView.setText(mData.getText());
 mViewHolder.image.setImageResource(mData.getImageId());
 //通过实例化后的Data数据，获取相应函数，进行属性的赋值

 return convertView;
 }
 class ViewHolder{
 //创建一个类，用于保存实例化的对象

 TextView textView;
 ImageView image;
 }
}

public class FirstAty extends AppCompatActivity {

 private ArrayList<Data> mList;

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

 initData();
 //初始化数据

 DataAdapter DataAdapter = new DataAdapter(FirstAty.this,R.layout.list_layout,mList);
 //实例化适配器

 ListView listView = (ListView) findViewById(R.id.list_view);
 //通过id实例化ListView

 listView.setAdapter(DataAdapter);
 //关联listView与适配器

 }

 private void initData() {
 mList = new ArrayList<>();//创建数据源的容器
 mList.add(new Data("camera",R.drawable.camera));
 mList.add(new Data("games_control",R.drawable.games_control));
 mList.add(new Data("ringtone",R.drawable.ringtone));
 mList.add(new Data("settings",R.drawable.settings));
 mList.add(new Data("speech_balloon",R.drawable.speech_balloon));
 }
}

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout 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"
 android:gravity="center_horizontal" 
 tools:context="comeinsteinford.github.firstapplication.FirstAty">

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

</RelativeLayout>

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:orientation="horizontal"
 android:layout_width="match_parent"
 android:layout_height="match_parent">
 <ImageView
 android:layout_width="70dp"
 android:layout_height="70dp"
 android:id="@+id/image"
 android:contentDescription="@string/text01"
 android:padding="10dp"/>
 <TextView
 android:layout_width="wrap_content"
 android:layout_height="wrap_content"
 android:textSize="30sp"
 android:id="@+id/textView"
 android:padding="10dp"/>
</LinearLayout>