Android图片浏览源码介绍

发布时间：2021-12-18 18:41:05 所属栏目：PHP教程来源：互联网

导读：Android手机操作系统的应用方式灵活，简单，深受广大编程爱好者的喜爱。尤其是它的开源代码，使得我们能够方便的得到自己想要的功能需求。今天我们就为大家带来了有关Android图片浏览的相关方法。首先是Android图片浏览中layout xml: ?xml version=1.0 enco

Android手机操作系统的应用方式灵活，简单，深受广大编程爱好者的喜爱。尤其是它的开源代码，使得我们能够方便的得到自己想要的功能需求。今天我们就为大家带来了有关Android图片浏览的相关方法。

首先是Android图片浏览中layout xml:

< ?xml version="1.0" encoding="utf-8"?>
< RelativeLayout xmlns:android="http://schemas.Android.com/apk/res/Android"
Android:layout_width="fill_parent"
Android:layout_height="fill_parent">
< ImageSwitcher Android:id="@+id/switcher"
Android:layout_width="fill_parent"
Android:layout_height="fill_parent"
Android:layout_alignParentTop="true"
Android:layout_alignParentLeft="true"
/>
< Gallery Android:id="@+id/gallery"
Android:background="#55000000"
Android:layout_width="fill_parent"
Android:layout_height="60dp"
Android:layout_alignParentBottom="true"
Android:layout_alignParentLeft="true"
Android:gravity="center_vertical"
Android:spacing="16dp"
/>
< /RelativeLayout>
layout里面用到了前面所说的两个控件，ImageSwitcher用啦显示全图，Gallery用来显示缩略图。着重看看ImageSwitcher,在ImageSwitcher1中需要实现ViewSwitcher.ViewFactory这个接口，这个接口里有个方法makeView，这样就产生了用来显示图片的view. ImageSwitcher调用过程是这样的，首先要有一个Factory为它提供一个View，然后ImageSwitcher就可以初始化各种资源了。注意在使用一个ImageSwitcher之前，一定要调用setFactory方法，要不setImageResource这个方法会报空指针异常。

下面是Android图片浏览代码：

package com.zx.imageswitcher;
import Android.app.Activity;
import Android.content.Context;
import Android.os.Bundle;
import Android.view.View;
import Android.view.ViewGroup;
import Android.view.animation.AnimationUtils;
import Android.widget.AdapterView;
import Android.widget.BaseAdapter;
import Android.widget.Gallery;
import Android.widget.ImageSwitcher;
import Android.widget.ImageView;
import Android.widget.ViewSwitcher;
import Android.widget.Gallery.LayoutParams;
public class ImageSwitcherTest extends Activity implements
AdapterView.OnItemSelectedListener, ViewSwitcher.ViewFactory{
private ImageSwitcher mSwitcher;
private Integer[] mThumbIds = {
R.drawable.sample_thumb_0, R.drawable.sample_thumb_1,
R.drawable.sample_thumb_2, R.drawable.sample_thumb_3,
R.drawable.sample_thumb_4, R.drawable.sample_thumb_5,
R.drawable.sample_thumb_6, R.drawable.sample_thumb_7};
private Integer[] mImageIds = {
R.drawable.sample_0, R.drawable.sample_1, R.drawable.sample_2,
R.drawable.sample_3, R.drawable.sample_4, R.drawable.sample_5,
R.drawable.sample_6, R.drawable.sample_7};
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
mSwitcher = (ImageSwitcher) findViewById(R.id.switcher);
mSwitcher.setFactory(this);
mSwitcher.setInAnimation(AnimationUtils.loadAnimation(this,
Android.R.anim.fade_in));
mSwitcher.setOutAnimation(AnimationUtils.loadAnimation(this,
Android.R.anim.fade_out));
Gallery g = (Gallery) findViewById(R.id.gallery);
g.setAdapter(new ImageAdapter(this));
g.setOnItemSelectedListener(this);
}
/*
* override for ViewSwitcher.ViewFactory#makeView()
*/
public View makeView() {
ImageView i = new ImageView(this);
i.setBackgroundColor(0xFF000000);
i.setScaleType(ImageView.ScaleType.FIT_CENTER);
i.setLayoutParams(new ImageSwitcher.LayoutParams
(LayoutParams.FILL_PARENT,
LayoutParams.FILL_PARENT));
return i;
}
/*
* override for
* AdapterView.OnItemSelectedListener#onItemSelected()
*/
public void onItemSelected(AdapterView parent,
View v, int position, long id) {
mSwitcher.setImageResource(mImageIds[position]);
}
/*
* override for AdapterView.OnItemSelectedListener
#onNothingSelected()
*/
public void onNothingSelected(AdapterView< ?> arg0) {
// TODO Auto-generated method stub
}
public class ImageAdapter extends BaseAdapter {
public ImageAdapter(Context c) {
mContext = c;
}
public int getCount() {
return mThumbIds.length;
}
public Object getItem(int position) {
return position;
}
public long getItemId(int position) {
return position;
}
public View getView(int position, View convertView,
ViewGroup parent) {
ImageView i = new ImageView(mContext);
i.setImageResource(mThumbIds[position]);
i.setAdjustViewBounds(true);
i.setLayoutParams(new Gallery.LayoutParams(
LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT));
i.setBackgroundResource(R.drawable.picture_frame);
return i;
}
private Context mContext;
}
}
从Android图片浏览的代码中看到还实现了AdapterView.OnItemSelectedListener，这样就需要重写onItemSelected()方法，然后在该方法中：mSwitcher.setImageResource(mImageIds[position]);这样就实现了图片在ImageSwitcher中的切换。

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