Go语言视频零基础入门到精通

jjuiwe

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:

java代码： < ?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>
复制代码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：

java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;

}



}
复制代码