安卓学习-（滚动布局：ListView）

8、ListView

简单的listview，可以滚动到屏幕外

privateString[] data= {"apple","Orange"};

privateList<Fruit> fruitList= newArrayList<Fruit>();

@Override

protected voidonCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

ArrayAdapter<String> adaper =new ArrayAdapter<String>(

MainActivity.this, android.R.layout.simple_list_item_1,data);

ListView listview = (ListView) findViewById(R.id.list_view);

listview.setAdapter(adaper);

}

9、ListView2 复杂listview实例

activity.xml

<?xml version="1.0"encoding="utf-8"?>

<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="vertical"

android:layout_width="match_parent"

android:layout_height="match_parent">

<ListView

android:id="@+id/list_view"

android:layout_width="match_parent"

android:layout_height="match_parent">

</ListView>

</LinearLayout>

MainActivity.java

packagecom.example.listviewtest;

importandroid.support.v7.app.AppCompatActivity;

importandroid.os.Bundle;

importandroid.view.View;

importandroid.widget.AdapterView;

importandroid.widget.ArrayAdapter;

importandroid.widget.ListView;

importandroid.widget.Toast;

importjava.util.ArrayList;

importjava.util.List;

public classMainActivity extendsAppCompatActivity {

privateList<Fruit> fruitList= newArrayList<Fruit>();

@Override

protected voidonCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

setContentView(R.layout.activity_main);

initFruits();// 初始化水果数据

FruitAdapter adapter =new FruitAdapter(MainActivity.this, R.layout.fruit_item,fruitList);

ListView listView = (ListView) findViewById(R.id.list_view);

listView.setAdapter(adapter);

listView.setOnItemClickListener(newAdapterView.OnItemClickListener() {

@Override

public voidonItemClick(AdapterView<?> parent, View view,

intposition, longid) {

Fruit fruit =fruitList.get(position);

Toast.makeText(MainActivity.this, fruit.getName(), Toast.LENGTH_SHORT).show();

}

});

}

private voidinitFruits() {

for(inti = 0; i <2; i++) {

Fruit apple =new Fruit("Apple", R.drawable.apple_pic);

fruitList.add(apple);

Fruit banana =new Fruit("Banana", R.drawable.banana_pic);

fruitList.add(banana);

Fruit orange =new Fruit("Orange", R.drawable.orange_pic);

fruitList.add(orange);

Fruit watermelon =new Fruit("Watermelon", R.drawable.watermelon_pic);

fruitList.add(watermelon);

Fruit pear =new Fruit("Pear", R.drawable.pear_pic);

fruitList.add(pear);

Fruit grape =new Fruit("Grape", R.drawable.grape_pic);

fruitList.add(grape);

Fruit pineapple =new Fruit("Pineapple", R.drawable.pineapple_pic);

fruitList.add(pineapple);

Fruit strawberry =new Fruit("Strawberry", R.drawable.strawberry_pic);

fruitList.add(strawberry);

Fruit cherry =new Fruit("Cherry", R.drawable.cherry_pic);

fruitList.add(cherry);

Fruit mango =new Fruit("Mango", R.drawable.mango_pic);

fruitList.add(mango);

}

}

}

Fruit.java

packagecom.example.listviewtest;

public classFruit {

privateString name;

private intimageId;

publicFruit(String name, intimageId) {

this.name= name;

this.imageId= imageId;

}

publicString getName() {

returnname;

}

public intgetImageId() {

returnimageId;

}

}

fruit_item.xml

<?xml version="1.0"encoding="utf-8"?>

<LinearLayoutxmlns:android="http://schemas.android.com/apk/res/android"

android:orientation="horizontal"

android:layout_width="match_parent"

android:layout_height="match_parent">

<ImageView

android:id="@+id/fruit_image"

android:layout_width="wrap_content"

android:layout_height="wrap_content"/>

<TextView

android:id="@+id/fruit_name"

android:layout_width="wrap_content"

android:layout_height="wrap_content"

android:layout_gravity="center_vertical"

android:layout_marginLeft="10dp"/>

</LinearLayout>

FruitAdapter.java

packagecom.example.listviewtest;

importandroid.content.Context;

importandroid.view.LayoutInflater;

importandroid.view.View;

importandroid.view.ViewGroup;

importandroid.widget.ArrayAdapter;

importandroid.widget.ImageView;

importandroid.widget.TextView;

importjava.util.List;

public classFruitAdapter extendsArrayAdapter<Fruit> {

private intresourceId;

publicFruitAdapter(Context context, int itemLayoutResourceId, List<Fruit> objects) {

super(context,itemLayoutResourceId, objects);

resourceId= itemLayoutResourceId;

}

@Override

//View convertView 用于将之前加载好的数据缓存

publicView getView(intposition, View convertView, ViewGroup parent) {

Fruit fruit = getItem(position);// 获取当前项的Fruit实例

View view;

ViewHolder viewHolder;

if(convertView == null) {

// 如果说当前子布局没有在缓存中，那么就在这里创建这个view

// 然后把布局加载到 viewHolder 里面；再把 viewHolder 放到 view中

// 然后把当前一个子布局的值填进去，最后返回view就行，不用对里面的viewHolder 做操作。

view = LayoutInflater.from(getContext()).inflate(resourceId, parent, false);

viewHolder =new ViewHolder();

viewHolder.fruitImage= (ImageView) view.findViewById (R.id.fruit_image);

viewHolder.fruitName= (TextView) view.findViewById (R.id.fruit_name);

view.setTag(viewHolder);// 将ViewHolder存储在View中

}else {

view = convertView;

viewHolder = (ViewHolder) view.getTag();// 重新获取ViewHolder

}

viewHolder.fruitImage.setImageResource(fruit.getImageId());

viewHolder.fruitName.setText(fruit.getName());

returnview;

}

classViewHolder {

ImageViewfruitImage;

TextViewfruitName;

}

}