使用ListView自定义布局
时间:2022-06-15
本文章向大家介绍使用ListView自定义布局,主要内容包括其使用实例、应用技巧、基本知识点总结和需要注意事项,具有一定的参考价值,需要的朋友可以参考一下。
使用ListView自定义布局
1.新建一个ListViewTest项目
2.修改MainActivity:
package com.example.listviewtest;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.AndroidCharacter;
import android.widget.ArrayAdapter;
import android.widget.ListView;
public class MainActivity extends AppCompatActivity {
private String[] data = {
"apple", "bannana", "pear", "orange",
"apple", "bannana", "pear", "orange",
"apple", "bannana", "pear", "orange",
"apple", "bannana", "pear", "orange",
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
ArrayAdapter<String> adapter = new ArrayAdapter<String>(
MainActivity.this, android.R.layout.simple_list_item_1,data
);
ListView listView = (ListView) findViewById(R.id.list_view);
listView.setAdapter(adapter);
}
}
3.修改activity_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns: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>
效果展示如下:
image.png
4.使用ListView
新建一个类Fruit:
package com.example.listviewtest;
public class Fruit {
private String name;
private int imageId;
public Fruit(String name, int imageId) {
this.name = name;
this.imageId = imageId;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
public int getImageId() {
return imageId;
}
public void setImageId(int imageId) {
this.imageId = imageId;
}
}
新建一个FruitAdapter:
package com.example.listviewtest;
import android.content.Context;
import android.support.annotation.IdRes;
import android.support.annotation.LayoutRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.Layout;
import android.util.Log;
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 java.util.List;
public class FruitAdapter extends ArrayAdapter<Fruit> {
private static final String TAG = "FruitAdapter";
private int resourceId;
public FruitAdapter( Context context,
int textViewResourceId,
List<Fruit> objects) {
super(context,textViewResourceId, objects);
resourceId = textViewResourceId;
}
@NonNull
@Override
public View getView(int position,
@Nullable View convertView,
@NonNull ViewGroup parent) {
Log.d(TAG, "position: "+position);
Fruit fruit = getItem(position); //获取当前Fruit实例
View view = LayoutInflater.from(getContext()).inflate(
resourceId,parent,false
);
ImageView fruitImage = (ImageView) view.findViewById(R.id.fruit_image);
TextView fruitName = (TextView) view.findViewById(R.id.fruit_name);
fruitImage.setImageResource(fruit.getImageId());
fruitName.setText(fruit.getName());
return view;
}
}
fruit_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="match_parent"
android:orientation="vertical">
<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>
MainActivity:
package com.example.listviewtest;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.AndroidCharacter;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private List<Fruit> fruitList = new ArrayList<>();
@Override
protected void onCreate(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);
}
private void initFruits() {
for (int i = 0; i <10 ; i++) {
Fruit apple = new Fruit("apple",R.drawable.apple);
fruitList.add(apple);
Fruit orange = new Fruit("orange",R.drawable.orange);
fruitList.add(orange);
}
}
}
提升ListView的运行效率
ListView这个控件实际上是很难用的,就是因为它很多细节可以优化,效率就是比较重要的一点.下面我们来优化下它的效率:
FruitAdapter:
package com.example.listviewtest;
import android.content.Context;
import android.support.annotation.IdRes;
import android.support.annotation.LayoutRes;
import android.support.annotation.NonNull;
import android.support.annotation.Nullable;
import android.text.Layout;
import android.util.Log;
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 java.util.List;
public class FruitAdapter extends ArrayAdapter<Fruit> {
private static final String TAG = "FruitAdapter";
private int resourceId;
public FruitAdapter(Context context,
int textViewResourceId,
List<Fruit> objects) {
super(context, textViewResourceId, objects);
resourceId = textViewResourceId;
}
@NonNull
@Override
public View getView(int position,
@Nullable View convertView,
@NonNull ViewGroup parent) {
Log.d(TAG, "position: " + position);
Fruit fruit = getItem(position); //获取当前Fruit实例
View view;
ViewHolder viewHolder;
if (convertView == null) {
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());
return view;
}
class ViewHolder {
ImageView fruitImage;
TextView fruitName;
}
}
这里对convertView进行重用,用viewHolder来取数据,提高了效率.
ListView的点击事件
修改MainActivity:
package com.example.listviewtest;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.AndroidCharacter;
import android.view.View;
import android.widget.AdapterView;
import android.widget.ArrayAdapter;
import android.widget.ListView;
import android.widget.Toast;
import java.util.ArrayList;
import java.util.List;
public class MainActivity extends AppCompatActivity {
private List<Fruit> fruitList = new ArrayList<>();
@Override
protected void onCreate(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(new AdapterView.OnItemClickListener() {
@Override
public void onItemClick(AdapterView<?> parent,
View view,
int position,
long id) {
Fruit fruit = fruitList.get(position);
Toast.makeText(MainActivity.this,
fruit.getName(),
Toast.LENGTH_SHORT
).show();
}
});
}
private void initFruits() {
for (int i = 0; i <10 ; i++) {
Fruit apple = new Fruit("apple",R.drawable.apple);
fruitList.add(apple);
Fruit orange = new Fruit("orange",R.drawable.orange);
fruitList.add(orange);
}
}
}
- JavaScript 教程
- JavaScript 编辑工具
- JavaScript 与HTML
- JavaScript 与Java
- JavaScript 数据结构
- JavaScript 基本数据类型
- JavaScript 特殊数据类型
- JavaScript 运算符
- JavaScript typeof 运算符
- JavaScript 表达式
- JavaScript 类型转换
- JavaScript 基本语法
- JavaScript 注释
- Javascript 基本处理流程
- Javascript 选择结构
- Javascript if 语句
- Javascript if 语句的嵌套
- Javascript switch 语句
- Javascript 循环结构
- Javascript 循环结构实例
- Javascript 跳转语句
- Javascript 控制语句总结
- Javascript 函数介绍
- Javascript 函数的定义
- Javascript 函数调用
- Javascript 几种特殊的函数
- JavaScript 内置函数简介
- Javascript eval() 函数
- Javascript isFinite() 函数
- Javascript isNaN() 函数
- parseInt() 与 parseFloat()
- escape() 与 unescape()
- Javascript 字符串介绍
- Javascript length属性
- javascript 字符串函数
- Javascript 日期对象简介
- Javascript 日期对象用途
- Date 对象属性和方法
- Javascript 数组是什么
- Javascript 创建数组
- Javascript 数组赋值与取值
- Javascript 数组属性和方法
- SSH设置别名访问远程服务器详细介绍
- Linux检查Swap交换空间的五个命令小结
- seaborn数据总体分布的可视化策略
- 配置 Apache 服务器禁止所有非法域名 访问自己的服务器
- Ubuntu16.04源码安装Mininet
- Kotlin基础学习之Deprecated与Suppress注解使用
- Centos 7下利用crontab定时执行任务详解
- 树莓派无线上网时无屏幕下发现树莓派IP的方法
- Ubuntu18.04安装opencv 3.2.0的解决方法
- Android MVP BaseFragment 通用式封装的实现
- 腾讯云服务器Centos挂载数据盘的方法
- CentOS 8.0.1905 安装 ZABBIX4.4版本 (已验证)
- seaborn分类变量的汇总展示
- Linux查看PCIe版本及速率的方法
- android自定义滚轴选择器