Gallery相册两种读取图片的方法
看了几个教程，学会 了两种方法实现Gallery相册，第一种是直接在res文件夹下放图片进行读取，第二种是读取sd卡的图片。
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首先，写好布局main.xml
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<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" android:orientation="vertical" android:layout_width="fill_parent" android:layout_height="fill_parent" ><Gallery android:id="@+id/gallery" android:layout_height="143px" android:layout_width="fill_parent" /><ImageView android:layout_width="239px" android:layout_height="218px" android:layout_x="38px" android:layout_y="184px" android:id="@+id/ImageView_photo" ></ImageView> </LinearLayout>
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?其二,在values文件夹下新建一个attr.xml
??<?xml version="1.0" encoding="utf-8"?>
<resources> <declare-styleable name="Gallery"> <attr name="android:galleryItemBackground" /> </declare-styleable> </resources>
? ?其三，写一个类，ImageAdapter.java
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??package com.chaowen;
import java.io.File;import java.util.ArrayList;import java.util.List;import android.R.color;import android.app.Activity;import android.content.Context;import android.content.res.Resources;import android.content.res.TypedArray;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Color;import android.text.AndroidCharacter;import android.util.DisplayMetrics;import android.view.View;import android.view.ViewGroup;import android.view.WindowManager;import android.widget.BaseAdapter;import android.widget.Gallery;import android.widget.ImageView;public class ImageAdapter extends BaseAdapter { private Context ctx; int mGalleryItemBackground; private List<String> lis; //这是第一种方法，直接用res文件夹下的图片 /*public int[] images = { R.drawable.img01,R.drawable.img02, R.drawable.img03,R.drawable.img04 };*/ public ImageAdapter(Context ctx,List<String> li){ try {this.ctx = ctx;lis = li ; //使用res/values/attr.xml中的<declare-styleable>定义的Gallery属性TypedArray a = ctx.obtainStyledAttributes(R.styleable.Gallery);//取得Gallery属性的Index idmGalleryItemBackground = a.getResourceId(R.styleable.Gallery_android_galleryItemBackground, Color.GREEN); //让对象的styleable属性能够反复使用a.recycle(); } catch (Exception e) { e.printStackTrace();} } @Overridepublic int getCount() {return lis.size();}@Overridepublic Object getItem(int position) { return position;} @Overridepublic long getItemId(int position) {return position;}@Overridepublic View getView(int position, View converView, ViewGroup parent) {try {ImageView v = new ImageView(this.ctx);//设定图片给ImageView对象Bitmap bm = BitmapFactory.decodeFile(lis.get(position).toString());v.setImageBitmap(bm);/*v.setImageResource(this.images[position]);*///重新设定图片的宽高v.setScaleType(ImageView.ScaleType.FIT_XY);//重新设定layout的宽高v.setLayoutParams(new Gallery.LayoutParams(128,128));v.setBackgroundResource(mGalleryItemBackground);return v;} catch (Exception e) { e.printStackTrace();}return null;} }?
最后，在主Activity类的代码如下
package com.chaowen;import java.io.File;import java.util.ArrayList;import java.util.List;import android.app.Activity;import android.net.Uri;import android.os.Bundle;import android.view.View;import android.widget.AdapterView;import android.widget.Gallery;import android.widget.ImageView;import android.widget.Toast;public class GalleryDemo extends Activity { /** Called when the activity is first created. */private Gallery mGallery;private ImageView imageView;private ImageAdapter imageAdapter; @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); mGallery =(Gallery) findViewById(R.id.gallery); imageView = (ImageView)findViewById(R.id.ImageView_photo); imageAdapter = new ImageAdapter(this,getSD()); mGallery.setAdapter(imageAdapter); mGallery.setOnItemClickListener(new Gallery.OnItemClickListener(){@Overridepublic void onItemClick(AdapterView<?> parent, View v, int position,long id) {//显示该图片是几号 Toast.makeText(GalleryDemo.this, "这是图片："+position+"号", Toast.LENGTH_SHORT).show(); //设置大图片 String photoURL = getSD().get(position); // imageView.setBackgroundResource(imageAdapter.images[position]); 这是用res资源下的图片的方法进行放大 imageView.setImageURI(Uri.parse(photoURL));} }); } /** * 获取sd卡的图片 * @return */private List<String> getSD() { /* 设定目前所在路径 */ List<String> it=new ArrayList<String>(); File f=new File("/sdcard/dcim/Camera/"); File[] files=f.listFiles(); /* 将所有文件存入ArrayList中 */ for(int i=0;i<files.length;i++) { File file=files[i]; if(getImageFile(file.getPath())) it.add(file.getPath()); } return it; } //获得文件的类型private boolean getImageFile(String fName) { boolean re; /* 取得扩展名 */ String end=fName.substring(fName.lastIndexOf(".")+1, fName.length()).toLowerCase(); /* 按扩展名的类型决定MimeType */ if(end.equals("jpg")||end.equals("gif")||end.equals("png") ||end.equals("jpeg")||end.equals("bmp")) { re=true; } else { re=false; } return re; } }??
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