Android入门第十三篇之Gallery + ImageSwitcher
?? 本文来自http://blog.csdn.net/hellogv/ ，引用必须注明出处！
?????? 上次讲了如何使用Gallery控件，这次就讲Gallery 与ImageSwitcher的结合使用，本文实现一个简单的浏览图片的功能。先贴出程序运行截图：
除了Gallery可以拖拉切换图片，我在ImageSwitcher控件加入了setOnTouchListener事件实现，使得ImageSwitcher也可以在拖拉中切换图片。本例子依然使用JAVA的反射机制来自动读取资源中的图片。
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main.xml的源码如下:
<?xml version="1.0" encoding="utf-8"?> <RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" android:layout_width="match_parent" android:layout_height="match_parent"> <ImageSwitcher android:id="@+id/switcher" android:layout_width="match_parent" android:layout_height="match_parent"/> <Gallery android:id="@+id/gallery" android:background="#55000000" android:layout_width="match_parent" android:layout_alignParentBottom="true" android:layout_alignParentLeft="true" android:gravity="center_vertical" android:spacing="16dp" android:layout_height="100dp"/> </RelativeLayout>
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程序的源码如下:
package com.testImageView; import java.lang.reflect.Field; import java.util.ArrayList; import android.app.Activity; import android.content.Context; import android.os.Bundle; import android.view.MotionEvent; import android.view.View; import android.view.View.OnTouchListener; 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.AdapterView.OnItemSelectedListener; import android.widget.Gallery.LayoutParams; import android.widget.ViewSwitcher.ViewFactory; public class testImageView extends Activity implements ViewFactory { private ImageSwitcher is; private Gallery gallery; private int downX,upX; private ArrayList<Integer> imgList=new ArrayList<Integer>();//图像ID @Override protected void onCreate(Bundle savedInstanceState) { // TODO Auto-generated method stub super.onCreate(savedInstanceState); setContentView(R.layout.main); //用反射机制来获取资源中的图片ID Field[] fields = R.drawable.class.getDeclaredFields(); for (Field field : fields) { if (!"icon".equals(field.getName()))//除了icon之外的图片 { int index = 0; try { index = field.getInt(R.drawable.class); } catch (IllegalArgumentException e) { // TODO Auto-generated catch block e.printStackTrace(); } catch (IllegalAccessException e) { // TODO Auto-generated catch block e.printStackTrace(); } //保存图片ID imgList.add(index); } } //设置ImageSwitcher控件 is = (ImageSwitcher) findViewById(R.id.switcher); is.setFactory(this); is.setInAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_in)); is.setOutAnimation(AnimationUtils.loadAnimation(this, android.R.anim.fade_out)); is.setOnTouchListener(new OnTouchListener(){ /* * 在ImageSwitcher控件上滑动可以切换图片 */ @Override public boolean onTouch(View v, MotionEvent event) { if(event.getAction()==MotionEvent.ACTION_DOWN) { downX=(int) event.getX();//取得按下时的坐标 return true; } else if(event.getAction()==MotionEvent.ACTION_UP) { upX=(int) event.getX();//取得松开时的坐标 int index=0; if(upX-downX>100)//从左拖到右，即看前一张 { //如果是第一，则去到尾部 if(gallery.getSelectedItemPosition()==0) index=gallery.getCount()-1; else index=gallery.getSelectedItemPosition()-1; } else if(downX-upX>100)//从右拖到左，即看后一张 { //如果是最后，则去到第一 if(gallery.getSelectedItemPosition()==(gallery.getCount()-1)) index=0; else index=gallery.getSelectedItemPosition()+1; } //改变gallery图片所选，自动触发ImageSwitcher的setOnItemSelectedListener gallery.setSelection(index, true); return true; } return false; } }); //设置gallery控件 gallery = (Gallery) findViewById(R.id.gallery); gallery.setAdapter(new ImageAdapter(this)); gallery.setOnItemSelectedListener(new OnItemSelectedListener(){ @Override public void onItemSelected(AdapterView<?> arg0, View arg1, int position, long arg3) { is.setImageResource(imgList.get(position)); } @Override public void onNothingSelected(AdapterView<?> arg0) { // TODO Auto-generated method stub } }); } //设置ImgaeSwitcher @Override public View makeView() { ImageView i = new ImageView(this); i.setBackgroundColor(0xFF000000); i.setScaleType(ImageView.ScaleType.CENTER);//居中 i.setLayoutParams(new ImageSwitcher.LayoutParams(//自适应图片大小 LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT)); return i; } public class ImageAdapter extends BaseAdapter { public ImageAdapter(Context c) { mContext = c; } public int getCount() { return imgList.size(); } 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(imgList.get(position)); i.setAdjustViewBounds(true); i.setLayoutParams(new Gallery.LayoutParams( LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT)); return i; } private Context mContext; } } ?
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