public class ImageItem implements Serializable {public String name;       //图片的名字public String path;       //图片的路径public long size;         //图片的大小public int width;         //图片的宽度public int height;        //图片的高度public String mimeType;   //图片的类型public long addTime;      //图片的创建时间/** 图片的路径和创建时间相同就认为是同一张图片 */@Overridepublic boolean equals(Object o) {if (o instanceof ImageItem) {ImageItem item = (ImageItem) o;return this.path.equalsIgnoreCase(item.path) && this.addTime == item.addTime;}return super.equals(o);}
}

这里最主要的字段是path 和addTime。

public class ImageDataSource implements LoaderManager.LoaderCallbacks<Cursor> {public static final int LOADER_ALL = 0;         //加载所有图片public static final int LOADER_CATEGORY = 1;    //分类加载图片private final String[] IMAGE_PROJECTION = {     //查询图片需要的数据列MediaStore.Images.Media.DISPLAY_NAME,   //图片的显示名称  aaa.jpgMediaStore.Images.Media.DATA,           //图片的真实路径  /storage/emulated/0/pp/downloader/wallpaper/aaa.jpgMediaStore.Images.Media.SIZE,           //图片的大小，long型  132492MediaStore.Images.Media.WIDTH,          //图片的宽度，int型  1920MediaStore.Images.Media.HEIGHT,         //图片的高度，int型  1080MediaStore.Images.Media.MIME_TYPE,      //图片的类型     image/jpegMediaStore.Images.Media.DATE_ADDED     //图片被添加的时间，long型  1450518608};private FragmentActivity activity;/*** 图片加载完成的回调接口*/private OnImagesLoadedListener loadedListener;/*** @param activity       用于初始化LoaderManager，需要兼容到2.3* @param path           指定扫描的文件夹目录，可以为 null，表示扫描所有图片* @param loadedListener 图片加载完成的监听*/public ImageDataSource(FragmentActivity activity, String path, OnImagesLoadedListener loadedListener) {this.activity = activity;this.loadedListener = loadedListener;LoaderManager loaderManager = activity.getSupportLoaderManager();if (path == null) {loaderManager.initLoader(LOADER_ALL, null, this);//加载所有的图片} else {//加载指定目录的图片Bundle bundle = new Bundle();bundle.putString("path", path);loaderManager.initLoader(LOADER_CATEGORY, bundle, this);}}@Overridepublic Loader<Cursor> onCreateLoader(int id, Bundle args) {CursorLoader cursorLoader = null;//扫描所有图片if (id == LOADER_ALL)//时间逆序cursorLoader = new CursorLoader(activity, MediaStore.Images.Media.EXTERNAL_CONTENT_URI, IMAGE_PROJECTION, null, null, IMAGE_PROJECTION[6] + " DESC");//扫描某个图片文件夹if (id == LOADER_CATEGORY)cursorLoader = new CursorLoader(activity, MediaStore.Images.Media.EXTERNAL_CONTENT_URI, IMAGE_PROJECTION, IMAGE_PROJECTION[1] + " like '%" + args.getString("path") + "%'", null, IMAGE_PROJECTION[6] + " DESC");return cursorLoader;}@Overridepublic void onLoadFinished(Loader<Cursor> loader, Cursor data) {//imageFolders.clear();ImageItem imageItem = new ImageItem();//只取第一个if (data != null) {// ArrayList<ImageItem> allImages = new ArrayList<>();   //所有图片的集合,不分文件夹if (data.moveToFirst()) {//查询数据String imageName = data.getString(data.getColumnIndexOrThrow(IMAGE_PROJECTION[0]));String imagePath = data.getString(data.getColumnIndexOrThrow(IMAGE_PROJECTION[1]));long imageSize = data.getLong(data.getColumnIndexOrThrow(IMAGE_PROJECTION[2]));int imageWidth = data.getInt(data.getColumnIndexOrThrow(IMAGE_PROJECTION[3]));int imageHeight = data.getInt(data.getColumnIndexOrThrow(IMAGE_PROJECTION[4]));String imageMimeType = data.getString(data.getColumnIndexOrThrow(IMAGE_PROJECTION[5]));long imageAddTime = data.getLong(data.getColumnIndexOrThrow(IMAGE_PROJECTION[6]));//long imageTokenTime = data.getLong(data.getColumnIndexOrThrow(IMAGE_PROJECTION[7]));/*  SimpleDateFormat sdf= new SimpleDateFormat("MM/dd/yyyy HH:mm:ss");//前面的lSysTime是秒数，先乘1000得到毫秒数，再转为java.util.Date类型java.util.Date dt = new Date(imageAddTime*1000);String sDateTime = sdf.format(dt);  //得到精确到秒的表示：08/31/2006 21:08:00dt = new Date(imageTokenTime);String sTakenTime =  sdf.format(dt);Log.e("latestImage","imageAddTime=="+sDateTime+":::::"+imageTokenTime);*///封装实体//ImageItem imageItem = new ImageItem();imageItem.name = imageName;imageItem.path = imagePath;imageItem.size = imageSize;imageItem.width = imageWidth;imageItem.height = imageHeight;imageItem.mimeType = imageMimeType;imageItem.addTime = imageAddTime;}}//回调接口，通知图片数据准备完成//  ImagePicker.getInstance().setImageFolders(imageFolders);loadedListener.onImagesLoaded(imageItem);}@Overridepublic void onLoaderReset(Loader<Cursor> loader) {//System.out.println("--------");}/** 所有图片加载完成的回调接口 */public interface OnImagesLoadedListener {void onImagesLoaded(ImageItem imageItem);}
}

从cursor取出第一张图片并赋值到ImageItem上，那么这次取数据就完成了，然后回调到相应的Activity上，在Activity中这样调用：

  new ImageDataSource(this, null, this);

在回调接口中处理数据：

@Overridepublic void onImagesLoaded(ImageItem imageItem) {latestImage = imageItem ;}

2，把从库中取出的图片展示出来

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="90dp"android:layout_height="135dp"android:orientation="vertical"android:background="@drawable/recommendphoto_bubble"android:padding="5dp"><TextViewandroid:layout_width="match_parent"android:layout_height="wrap_content"android:textSize="12sp"android:text="你可能要发送的照片："/><ImageViewandroid:id="@+id/recommendphoto_img"android:layout_width="match_parent"android:layout_height="match_parent"android:layout_marginTop="2dp"android:scaleType="centerCrop"android:background="@drawable/recommendphoto_bg"android:layout_marginBottom="7dp"/></LinearLayout>

布局文件很简单，就两个控件和背景,pop 的具体实现：

/*** 推荐图片提示框 刚拍完照后，显示你可能要发送的图片**/
public class RecommendPhotoPop extends PopupWindow {/****/private ImageView iv;/****/private static Context context;public RecommendPhotoPop(Context context) {this.context = context;View view = LayoutInflater.from(context).inflate(R.layout.layout_recommendphoto_pop,null,false);iv = (ImageView) view.findViewById(R.id.recommendphoto_img);setContentView(view);setWidth(dip2px(90));setHeight(dip2px(135));setFocusable(false);setBackgroundDrawable(new BitmapDrawable());// 设置点击其他地方 就消失 (只设置这个，没有效果)setOutsideTouchable(true);}public  void setImgPath(final String path) {iv.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {}});Glide.with(context).load(path).crossFade().centerCrop().into(iv);}/*** 显示图片提示* @param context* @param view*/public  static  RecommendPhotoPop recommendPhoto(Context context, View view,String path) {final RecommendPhotoPop recommendPhotoPop = new RecommendPhotoPop(context);recommendPhotoPop.setImgPath(path);int x = getScreenWidth(context) - dip2px(92);int y = getScreenHeight(context) - view.getMeasuredHeight() - dip2px(138);// recommendPhotoPop.showAsDropDown(view);recommendPhotoPop.showAtLocation(view, Gravity.NO_GRAVITY,x,y);return recommendPhotoPop;}/** dip转换px */public  static int dip2px(int dip) {final float scale = context.getResources().getDisplayMetrics().density;return (int) (dip * scale + 0.5f);}/** pxz转换dip */public static int px2dip(int px) {final float scale = context.getResources().getDisplayMetrics().density;return (int) (px / scale + 0.5f);}/*** 获得屏幕高度** @param context* @return*/public  static int getScreenWidth(Context context) {WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);DisplayMetrics outMetrics = new DisplayMetrics();wm.getDefaultDisplay().getMetrics(outMetrics);return outMetrics.widthPixels;}/*** 获得屏幕宽度** @param context* @return*/public  static int getScreenHeight(Context context) {WindowManager wm = (WindowManager) context.getSystemService(Context.WINDOW_SERVICE);DisplayMetrics outMetrics = new DisplayMetrics();wm.getDefaultDisplay().getMetrics(outMetrics);return outMetrics.heightPixels;}}

这里pop也实现了，看看主Activity 的实现：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayoutxmlns:android="http://schemas.android.com/apk/res/android"xmlns:app="http://schemas.android.com/apk/res-auto"xmlns:tools="http://schemas.android.com/tools"android:layout_width="match_parent"android:layout_height="match_parent"android:background="@color/colorPrimary"><Buttonandroid:id="@+id/btn"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="你想发送的图片"android:layout_alignParentBottom="true"android:layout_alignParentRight="true"android:layout_margin="5dp"/><ImageViewandroid:id="@+id/image"android:layout_width="400dp"android:layout_height="400dp" /></RelativeLayout>

代码：

public class MainActivity extends AppCompatActivity implements ImageDataSource.OnImagesLoadedListener {private ImageView imageView ;private Button btn ;private ImageItem latestImage ;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);imageView = (ImageView)findViewById(R.id.image);btn = (Button)findViewById(R.id.btn);/*** 申请权限*/if(ContextCompat.checkSelfPermission(this, Manifest.permission.READ_EXTERNAL_STORAGE)!= PackageManager.PERMISSION_GRANTED){ActivityCompat.requestPermissions(this,new String[]{Manifest.permission.READ_EXTERNAL_STORAGE},0 );}else {new ImageDataSource(this, null, this);}btn.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {RecommendPhotoPop.recommendPhoto(MainActivity.this,btn,latestImage.path);}});//String url = "https://ws1.sinaimg.cn/large/610dc034ly1fiednrydq8j20u011itfz.jpg";// Glide.with(this).load(url).diskCacheStrategy(DiskCacheStrategy.ALL).into(imageView);}@Overridepublic void onImagesLoaded(ImageItem imageItem) {latestImage = imageItem ;Glide.with(this).load(imageItem.path).into(imageView);}@Overridepublic void onRequestPermissionsResult(int requestCode, @NonNull String[] permissions, @NonNull int[] grantResults) {super.onRequestPermissionsResult(requestCode, permissions, grantResults);switch (requestCode){case 0:if(grantResults[0] == PackageManager.PERMISSION_GRANTED){new ImageDataSource(this, null, this);}break;}}

附上权限和依赖：

<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE"/>

 compile 'com.github.bumptech.glide:glide:3.7.0'

源码： 高仿微信你可能要发送的图片