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一、ExpandableListView介绍 　　　　一个垂直滚动的显示两个级别（Child,Group）列表项的视图，列表项来自ExpandableListAdapter 。组可以单独展开。 　　1.重要方法 　　　　　　expandGroup(int groupPos) :在分组列表视图中展开一组，　　　　　　setSelectedGroup(int groupPosition) ：设置选择指定的组。　　　　　　setSelectedChild(int groupPosition, int childPosition, boolean shouldExpandGroup) ：设置选择指定的子项。　　　　　　getPackedPositionGroup(long packedPosition) ：返回所选择的组　　　　　　getPackedPositionForChild(int groupPosition, int childPosition) ：返回所选择的子项　　　　　　getPackedPositionType(long packedPosition) ：返回所选择项的类型（Child,Group）　　　　　　isGroupExpanded(int groupPosition) :判断此组是否展开　　2.代码：ExpandableListContextMenuInfo menuInfo=(ExpandableListContextMenuInfo)item.getMenuInfo();String title=((TextView)menuInfo.targetView).getText().toString();int type=ExpandableListView.getPackedPositionType(menuInfo.packedPosition);if (type==ExpandableListView.PACKED_POSITION_TYPE_CHILD) {int groupPos =ExpandableListView.getPackedPositionGroup(menuInfo.packedPosition);int childPos =ExpandableListView.getPackedPositionChild(menuInfo.packedPosition);二、ExpandableListAdapter　　　　一个接口，将基础数据链接到一个ExpandableListView。此接口的实施将提供访问Child的数据（由组分类），并实例化的Child和Group。 getChildId(int groupPosition, int childPosition) 获取与在给定组给予孩子相关的数据。 　　　　getChildrenCount(int groupPosition) 返回在指定Group的Child数目。

android imageview 入门实例 主要实现了 图片以及背景的切换效果，详见截图

[实例简介]Open GL 入门级示例 [实例截图] [核心代码]package com.china.gltry;import javax.microedition.khronos.egl.EGL10;import javax.microedition.khronos.egl.EGL11;import javax.microedition.khronos.egl.EGLConfig;import javax.microedition.khronos.egl.EGLContext;import javax.microedition.khronos.egl.EGLDisplay;import javax.microedition.khronos.egl.EGLSurface;import javax.microedition.khronos.opengles.GL;import android.view.SurfaceHolder;/** * An EGL helper class. */public class EGLHelper{ public EGLHelper() { } /** * Initialize EGL for a given configuration spec. * @param configSpec */ public void start(int[] configSpec){ /* * Get an EGL instance */ mEgl = (EGL10) EGLContext.getEGL(); /* * Get to the default display. */ mEglDisplay = mEgl.eglGetDisplay(EGL10.EGL_DEFAULT_DISPLAY); /* * We can now initialize EGL for that display */ int[] version = new int[2]; mEgl.eglInitialize(mEglDisplay, version); EGLConfig[] configs = new EGLConfig[1]; int[] num_config = new int[1]; mEgl.eglChooseConfig(mEglDisplay, configSpec, configs, 1, num_config); mEglConfig = configs[0]; /* * Create an OpenGL ES context. This must be done only once, an * OpenGL context is a somewhat heavy object. */ mEglContext = mEgl.eglCreateContext(mEglDisplay, mEglConfig, EGL10.EGL_NO_CONTEXT, null); mEglSurface = null; } /* * Create and return an OpenGL surface */ public GL createSurface(SurfaceHolder holder) { /* * The window size has changed, so we need to create a new * surface. */ if (mEglSurface != null) { /* * Unbind and destroy the old EGL surface, if * there is one. */ mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_CONTEXT); mEgl.eglDestroySurface(mEglDisplay, mEglSurface); } /* * Create an EGL surface we can render into. */ mEglSurface = mEgl.eglCreateWindowSurface(mEglDisplay, mEglConfig, holder, null); /* * Before we can issue GL commands, we need to make sure * the context is current and bound to a surface. */ mEgl.eglMakeCurrent(mEglDisplay, mEglSurface, mEglSurface, mEglContext); GL gl = mEglContext.getGL(); return gl; } /** * Display the current render surface. * @return false if the context has been lost. */ public boolean swap() { mEgl.eglSwapBuffers(mEglDisplay, mEglSurface); /* * Always check for EGL_CONTEXT_LOST, which means the context * and all associated data were lost (For instance because * the device went to sleep). We need to sleep until we * get a new surface. */ return mEgl.eglGetError() != EGL11.EGL_CONTEXT_LOST; } public void finish() { if (mEglSurface != null) { mEgl.eglMakeCurrent(mEglDisplay, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_SURFACE, EGL10.EGL_NO_CONTEXT); mEgl.eglDestroySurface(mEglDisplay, mEglSurface); mEglSurface = null; } if (mEglContext != null) { mEgl.eglDestroyContext(mEglDisplay, mEglContext); mEglContext = null; } if (mEglDisplay != null) { mEgl.eglTerminate(mEglDisplay); mEglDisplay = null; } } EGL10 mEgl; EGLDisplay mEglDisplay; EGLSurface mEglSurface; EGLConfig mEglConfig; EGLContext mEglContext;}

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