Gallery 組件用于拖拽瀏覽圖片,下面我們就來(lái)看一下如何實(shí)現(xiàn)。
1.布局文件很簡(jiǎn)單:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/MyLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FFFFFF"
android:orientation="vertical" >
<Gallery
android:id="@+id/myGallery"
android:gravity="center_vertical"
android:layout_width="match_parent"
android:layout_height="wrap_content" ></Gallery>
</LinearLayout>
2.自定義適配器類,可以直接覆寫 BaseAdapter 類中的幾個(gè)方法。
package org.yayun.demo;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.Gallery;
import android.widget.ImageView;
import android.widget.Gallery.LayoutParams;
public class ImageGalleryAdapter extends BaseAdapter {
private Context context;
private int imgRes[] = new int[] { R.drawable.ispic_a, R.drawable.ispic_b,
R.drawable.ispic_c, R.drawable.ispic_d, R.drawable.ispic_e, };
public ImageGalleryAdapter(Context c) {//構(gòu)造方法,用于獲取上下文對(duì)象
this.context = c;
}
public int getCount() {
return imgRes.length;
}
public Object getItem(int position) {
return imgRes[position];
}
public long getItemId(int position) {
return imgRes[position];
}
public View getView(int position, View convertView, ViewGroup parent) {
ImageView img = new ImageView(this.context);
img.setBackgroundColor(0xFFFFFFFF);
img.setImageResource(this.imgRes[position]);//設(shè)置資源
img.setScaleType(ImageView.ScaleType.CENTER);//居中顯示
img.setLayoutParams(new Gallery.LayoutParams(LayoutParams.WRAP_CONTENT,
LayoutParams.WRAP_CONTENT));
return img;
}
}
3.MainActivity.java:
package org.yayun.demo;
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.AdapterView;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Gallery;
public class MainActivity extends Activity {
private Gallery gallery;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState); // 生命周期方法
super.setContentView(R.layout.main); // 設(shè)置要使用的布局管理器
gallery = (Gallery) findViewById(R.id.myGallery);
gallery.setAdapter(new ImageGalleryAdapter(this));
gallery.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Toast.makeText(MainActivity.this,
"您選擇了第" + String.valueOf(position + 1) + "張圖片",
Toast.LENGTH_SHORT).show();
}
});
}
}
4.運(yùn)行實(shí)例如下:
http://wiki.jikexueyuan.com/project/android-in-action/images/31.png" alt="" />
這時(shí)的 Gallery 我們用 SimpleAdapter 類完成。
1.布局文件:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:id="@+id/MyLayout"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:background="#FFFFFF"
android:gravity="bottom"
android:orientation="vertical" >
<ImageSwitcher
android:id="@+id/imageSwitcher"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
</ImageSwitcher>
<Gallery
android:id="@+id/gallery"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:gravity="center_vertical"
android:spacing="5dp" />
</LinearLayout>
2.定義顯示模板:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="#FFFFFF"
android:orientation="horizontal" >
<ImageView
android:id="@+id/img"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:scaleType="center" />
</LinearLayout>
3.MainActivity.java 程序:
package org.yayun.demo;
import java.lang.reflect.Field;
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.view.View;
import android.widget.AdapterView;
import android.widget.ImageSwitcher;
import android.widget.ImageView;
import android.widget.SimpleAdapter;
import android.widget.Toast;
import android.widget.AdapterView.OnItemClickListener;
import android.widget.Gallery.LayoutParams;
import android.widget.Gallery;
import android.widget.ViewSwitcher.ViewFactory;
public class MainActivity extends Activity {
private Gallery gallery;
private List<Map<String, Integer>> list = new ArrayList<Map<String, Integer>>();
private SimpleAdapter simpleAdapter;
private ImageSwitcher imageSwitcher;
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState); // 生命周期方法
super.setContentView(R.layout.main); // 設(shè)置要使用的布局管理器
initAdapter();
gallery = (Gallery) findViewById(R.id.gallery);
imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher);
imageSwitcher.setFactory(new ViewFactory() {
public View makeView() {
ImageView imageView = new ImageView(MainActivity.this);
imageView.setBackgroundColor(0xFFFFFFFF);
imageView.setScaleType(ImageView.ScaleType.CENTER);
imageView.setLayoutParams(new ImageSwitcher.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
return imageView;
}
});
gallery.setAdapter(simpleAdapter);
gallery.setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
Map<String, Integer> map = (Map<String, Integer>) MainActivity.this.simpleAdapter
.getItem(position);// 取出map
MainActivity.this.imageSwitcher.setImageResource(map.get("img"));// 設(shè)置顯示圖片
}
});
}
private void initAdapter() {
Field[] fields = R.drawable.class.getDeclaredFields();// Java反射機(jī)制獲取所有資源圖片
for (int i = 0; i < fields.length; i++) {
if (fields[i].getName().startsWith("ispic_")) {// 判斷開(kāi)頭
Map<String, Integer> map = new HashMap<String, Integer>();
try {
map.put("img", fields[i].getInt(R.drawable.class));
} catch (IllegalArgumentException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IllegalAccessException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
this.list.add(map);
}
}
simpleAdapter = new SimpleAdapter(this, this.list,
R.layout.grid_layout, new String[] { "img" },
new int[] { R.id.img });
}
}
4.運(yùn)行實(shí)例:
http://wiki.jikexueyuan.com/project/android-in-action/images/32.png" alt="" />