android学习之--网格视图(GridView)和图像切换器(ImageSwitcher)

         GridView用于在界面上按行、列分布显示多个组件。GridView和ListView有共同父类:AbsListView。

GridView与ListView的差别在于:ListView仅仅在一个方向上分布,GridView在两个方向上分布。所以使用GridView时一般都指定numColumns大于1,否则该属性默认值为1。就意味着改GridView仅仅有一列,那就变成了ListView

GridView的xml属性

android学习之--网格视图(GridView)和图像切换器(ImageSwitcher)

android:strtchMode 的值为:

android学习之--网格视图(GridView)和图像切换器(ImageSwitcher)

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     ImageSwitcher由FrameLayout派生而出,ImageSwitcher组件与ImageView非常相似,可是ImageSwitcher多一个功能:它所显示的图片切换时能够设置动画效果。

使用ImageSwitcher时往往须要为它设置一个ImageSwitcher.ViewFactory的makeView()方法来负责显示ImageView

以下结合GridView和ImageSwitcher来实现一个样例

(1)activity_main.xml     布局GridView和ImageSwitcher

<LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:gravity="center_horizontal">
<GridView
android:id="@+id/grid"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:horizontalSpacing="1dp"
android:verticalSpacing="2dp"
android:numColumns="4"/>
<ImageSwitcher
android:id="@+id/imageSwitch"
android:layout_gravity="center_vertical|center_horizontal"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/> </LinearLayout>

(2)img.xml        布局imageView 用于显示GridView的图片

<?xml version="1.0" encoding="UTF-8"?

>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="horizontal"
android:layout_width="fill_parent"
android:layout_height="fill_parent"> <ImageView
android:id="@+id/img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"/>
</LinearLayout>

(3)MainActivity.java

package com.example.viewimage;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map; import android.app.Activity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.view.animation.AnimationUtils;
import android.widget.AdapterView;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.AdapterView.OnItemSelectedListener;
import android.widget.GridView;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.ImageView.ScaleType;
import android.widget.SimpleAdapter;
import android.widget.ViewSwitcher.ViewFactory; public class MainActivity extends Activity { //定义组件
private GridView gredView = null;
private ImageSwitcher imageSwt =null; @Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//获取布局组件
gredView = (GridView) findViewById(R.id.grid);
imageSwt = (ImageSwitcher) findViewById(R.id.imageSwitch);
//图片
final int images[] = new int[]{
R.drawable.name01,R.drawable.name02,R.drawable.name03,R.drawable.name04,
R.drawable.name05,R.drawable.name06,R.drawable.name07,R.drawable.name08,
R.drawable.name09,R.drawable.name10,R.drawable.name11,R.drawable.name12,
R.drawable.name13,R.drawable.name14,R.drawable.name15,R.drawable.name16
};
//创建list集合。存储图片
List<Map<String,Object>> list = new ArrayList<Map<String,Object>>();
for(int i=0;i<images.length;i++){
Map<String,Object> map = new HashMap<String,Object>();
map.put("img", images[i]);
list.add(map);
}
//设置图片更换效果
//淡入效果
imageSwt.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in));
//淡出效果
imageSwt.setOutAnimation(AnimationUtils.loadAnimation(this,android.R.anim.fade_out));
//设置图片转换效果
imageSwt.setFactory(new ViewFactory() { @Override
public View makeView() {
ImageView imageView = new ImageView(MainActivity.this);
imageView.setLayoutParams(new ImageSwitcher.LayoutParams(300, 300));
imageView.setScaleType(ScaleType.FIT_CENTER);
return imageView;
}
});
//设置适配器
SimpleAdapter simpleAdapter = new SimpleAdapter(this, list, R.layout.img, new String[]{"img"}, new int[]{R.id.img});
//适配器
gredView.setAdapter(simpleAdapter);
//选中事件监听
gredView.setOnItemSelectedListener(new OnItemSelectedListener() { @Override
public void onItemSelected(AdapterView<?> parent, View view,
int position, long id) {
Log.i("onItemSelected", "onItemSelected");
imageSwt.setImageResource(images[position]);
} @Override
public void onNothingSelected(AdapterView<? > parent) {
// TODO Auto-generated method stub }
});
//点击事件监听
gredView.setOnItemClickListener(new OnItemClickListener() { @Override
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Log.i("onItemClick", "onItemClick");
imageSwt.setImageResource(images[position]); }
});
} }

执行效果例如以下:

android学习之--网格视图(GridView)和图像切换器(ImageSwitcher)

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