Android之Gallery

一. 初步认识

src

package cn.android.lyj;import android.app.Activity;import android.content.Context;import android.content.res.TypedArray;import android.os.Bundle;import android.view.ContextMenu;import android.view.MenuItem;import android.view.View;import android.view.ViewGroup;import android.view.ContextMenu.ContextMenuInfo;import android.widget.AdapterView;import android.widget.BaseAdapter;import android.widget.Gallery;import android.widget.ImageView;import android.widget.Toast;import android.widget.AdapterView.AdapterContextMenuInfo;import android.widget.AdapterView.OnItemClickListener;public class Activity_01 extends Activity {@Overridepublic void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.main);// Reference the Gallery viewGallery g = (Gallery) findViewById(R.id.gallery);// Set the adapter to our custom adapter (below)g.setAdapter(new ImageAdapter(this));// Set a item click listener, and just Toast the clicked positiong.setOnItemClickListener(new OnItemClickListener() {public void onItemClick(AdapterView parent, View v, int position, long id) {Toast.makeText(Activity_01.this, "" + position,Toast.LENGTH_SHORT).show();}});// We also want to show context menu for longpressed items in the// galleryregisterForContextMenu(g);}@Overridepublic void onCreateContextMenu(ContextMenu menu, View v, ContextMenuInfo menuInfo) {menu.add(R.string.gallery_2_text);menu.add("hello");}@Overridepublic boolean onContextItemSelected(MenuItem item) {AdapterContextMenuInfo info = (AdapterContextMenuInfo) item.getMenuInfo();Toast.makeText(this, "Longpress: " + info.position, Toast.LENGTH_SHORT).show();return true;}public class ImageAdapter extends BaseAdapter {int mGalleryItemBackground;public ImageAdapter(Context c) {mContext = c;TypedArray a = obtainStyledAttributes(R.styleable.Gallery1);mGalleryItemBackground = a.getResourceId(R.styleable.Gallery1_android_galleryItemBackground, 0);a.recycle();}public int getCount() {return mImageIds.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(mImageIds[position]);i.setScaleType(ImageView.ScaleType.FIT_XY); //图片在北京图片中得位置i.setLayoutParams(new Gallery.LayoutParams(136, 88)); //修改存放此图片的view的大小比例// The preferred Gallery item backgroundi.setBackgroundResource(mGalleryItemBackground);return i;}private Context mContext;private Integer[] mImageIds = { R.drawable.gallery_photo_1,R.drawable.gallery_photo_2, R.drawable.gallery_photo_3,R.drawable.gallery_photo_4, R.drawable.gallery_photo_5,R.drawable.gallery_photo_6, R.drawable.gallery_photo_7,R.drawable.gallery_photo_8 };}}

main.xml

<?xml version="1.0" encoding="utf-8"?><Gallery xmlns:android="http://schemas.android.com/apk/res/android" android:id="@+id/gallery"android:layout_width="match_parent"android:layout_height="wrap_content"/>

attrs.xml

<?xml version="1.0" encoding="utf-8"?><resources>  <declare-styleable name="Gallery1"> <attr name="android:galleryItemBackground" /> </declare-styleable></resources>

strings.xml

<?xml version="1.0" encoding="utf-8"?><resources> <string name="gallery_2_text">Testing</string> <string name="app_name">Gallery</string></resources>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android" package="cn.android.lyj" android:versionCode="1" android:versionName="1.0" > <uses-sdk android:minSdkVersion="10" /> <application android:icon="@drawable/ic_launcher" android:label="@string/app_name" > <activity android:label="@string/app_name" android:name=".Activity_01" > <intent-filter > <action android:name="android.intent.action.MAIN" /> <category android:name="android.intent.category.LAUNCHER" /> </intent-filter> </activity> </application></manifest>

二. 运行结果

运行后

点击第一幅图片后

长按出现上下文菜单

点击其中一项后

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