【Android基础入门〖13〗】Gallery

1    在 xml 布局中添加 Gallery

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<Gallery
android:id="@+id/gallery"
android:layout_width="match_parent"
android:layout_height="match_parent"/>
</LinearLayout>

2    自定义 ImageAdapter

package com.example.gallery;
import java.util.List;
import android.content.Context;
import android.content.res.TypedArray;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
@SuppressWarnings("deprecation")
public class ImageAdapter extends BaseAdapter {

private Context context;
private List<Integer> list;
private TypedArray typedArray;
private int item_background;

public ImageAdapter(Context context ,List<Integer> list)
{
this.context=context;
this.list=list;
this.typedArray = context.obtainStyledAttributes(R.styleable.gallery_style);
item_background=typedArray.getResourceId(R.styleable.gallery_style_android_galleryItemBackground, 0);
typedArray.recycle();
}
@Override
public int getCount() {
return list.size();
}
@Override
public Object getItem(int position) {
return position;
}
@Override
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
ImageView imageView = new ImageView(context);
//设置显示的图片
imageView.setImageResource(list.get(position));

//设置伸缩规格
imageView.setScaleType(ImageView.ScaleType.FIT_XY);

//设置布局参数
imageView.setLayoutParams(new Gallery.LayoutParams(150,100));

//设置背景边框
imageView.setBackgroundResource(item_background);

return imageView;
}
}

3    每个 ImageView 的背景参数

<?xml version="1.0" encoding="utf-8"?>
<resources>
<declare-styleable name="gallery_style">
<attr name="android:galleryItemBackground" />
</declare-styleable>
</resources>

4    在 MainActivity 中绑定数据与设置监听

package com.example.gallery;
import java.util.ArrayList;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Gallery;
import android.widget.Toast;
@SuppressWarnings("deprecation")
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Gallery gallery=(Gallery)findViewById(R.id.gallery);

ArrayList<Integer>list=new ArrayList<Integer>();
list.add(R.drawable.img1);
list.add(R.drawable.img2);
list.add(R.drawable.img3);
list.add(R.drawable.img4);
list.add(R.drawable.img5);
list.add(R.drawable.img6);
list.add(R.drawable.img7);

ImageAdapter adapter=new ImageAdapter(this,list);
gallery.setAdapter(adapter);

gallery.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
@Override
public void onItemSelected(AdapterView<?> parent, View v,int position, long id) {
Toast.makeText(getApplicationContext(), "选择了:  "+
String.valueOf(position), Toast.LENGTH_SHORT).show();
}

@Override
public void onNothingSelected(AdapterView<?> arg0) {
//这里不做响应
}
});
}
}

5    图片资源

6    结果展示