总体思路就是开线程获取第一帧并存到本地，用数据库保存播放链接和第一帧图片的本地地址，第二次打开做判断，先在数据库存储查询，看是否存在，如果存在就把地址取出来加载。
首先你需要写一个Thread类，用来调用获取视频第一帧的封面，为什么要建一个线程类呢，因为在获取封面过程中调用包括setDataSource(String url)和getFrameAtTime(long timeMs,int option)方法都是很耗时的操作，所以要在子线程中获取，获取完成之后，在用handler去更新适配器UI。
好了，下面咱们开始吧：
Thread类：
package cn.wangcy.demo.ffcd.thread;
import android.content.Context;
import android.graphics.Bitmap;
import android.graphics.Matrix;
import android.media.MediaMetadataRetriever;
import android.os.Build;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.widget.ImageView;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import cn.wangcy.demo.ffcd.bean.VideoDataBean;
import cn.wangcy.demo.ffcd.db.DbManager;
import cn.wangcy.demo.ffcd.utils.LogUtils;
import cn.wangcy.demo.ffcd.utils.PictureUtils;
/**
* Created by wangchuanyu on 2018/7/16.
*/
public class CreateFirstFrameBitmapThread extends Thread {
private List<VideoDataBean> mDatas;
private int width = 0;
private int height = 0;
private ImageView videoCover = null;
private final String OutPutFileDirPath = Environment.getExternalStorageDirectory() + "/first_frame";
private Handler handler;
private DbManager manager;
private long fileLength;
private int posIndex = 0;
public CreateFirstFrameBitmapThread(List<VideoDataBean> mDatas, int width, int height, ImageView videoCover, Handler handler) {
this.mDatas = mDatas;
this.width = width;
this.height = height;
this.videoCover = videoCover;
this.handler = handler;
}
public CreateFirstFrameBitmapThread(Context context, List<VideoDataBean> mDatas, Handler handler) {
this.mDatas = mDatas;
this.handler = handler;
manager = new DbManager(context);
}
public CreateFirstFrameBitmapThread(Context context, List<VideoDataBean> mDatas, Handler handler, int i) {
this.mDatas = mDatas;
this.handler = handler;
this.posIndex = i;
manager = new DbManager(context);
}
public CreateFirstFrameBitmapThread() {
}
@Override
public void run() {
super.run();
for (int i = posIndex; i < mDatas.size(); i++) {
createBitmapFromVideoPath(i, mDatas.get(i).getmVideoUrl());
}
}
/**
* 获取第一帧的方法，通过上方for循环进行获取第一帧
* @param positon
* @param url
*/
public void createBitmapFromVideoPath(int positon, String url) {
synchronized (this) {
Bitmap bitmap = null;
MediaMetadataRetriever retriever = new MediaMetadataRetriever();
try {
if (Build.VERSION.SDK_INT >= 12) {
retriever.setDataSource(url, new HashMap<String, String>());
} else {
retriever.setDataSource(url);
}
bitmap = retriever.getFrameAtTime(1000, MediaMetadataRetriever.OPTION_CLOSEST_SYNC);
String len = retriever.extractMetadata(MediaMetadataRetriever.METADATA_KEY_DURATION);
fileLength = TextUtils.isEmpty(len) ? 0 : Long.valueOf(len);
Bitmap bitmapNew = /*scaleImage(bitmap)*/bitmap;
// Bitmap bitmapNew = /*scaleImage(bitmap)*/zoomImage(bitmap,100,100);
String path = PictureUtils.saveImageToSDForEdit(bitmapNew, OutPutFileDirPath, positon + "_FirstFrame_ffcd" + PictureUtils.POSTFIX);
VideoDataBean bean = mDatas.get(positon);
manager.addImage(bean);
// sendPic(bitmapNew, positon);
sendPic(path, bitmapNew, positon);
} catch (IllegalArgumentException ex) {
ex.printStackTrace();
} catch (RuntimeException ex) {
ex.printStackTrace();
} catch (Exception ex) {
} finally {
try {
retriever.release();
} catch (RuntimeException ex) {
ex.printStackTrace();
}
}
}
}
/**
* 压缩图片
* @param bitmap
* @param newWidth
* @param newHeight
* @return
*/
public static Bitmap zoomImage(Bitmap bitmap, int newWidth, int newHeight) {
// 获得图片的宽高
int width = bitmap.getWidth();
int height = bitmap.getHeight();
// 计算缩放比例
float scaleWidth = ((float) newWidth) / width;
float scaleHeight = ((float) newHeight) / height;
// 取得想要缩放的matrix参数
Matrix matrix = new Matrix();
matrix.postScale(scaleWidth, scaleHeight);
// 得到新的图片
return Bitmap.createBitmap(bitmap, 0, 0, width, height, matrix, true);
}
/**
* 发送图片到handler，更新UI
* @param path
* @param bitmap
* @param positon
*/
public void sendPic(String path, Bitmap bitmap, int positon) {
Message msg = new Message();
msg.what = 0;
msg.arg1 = positon;
msg.obj = path;
handler.sendMessage(msg);
}
/**
* 发送图片到handler，更新UI(以list形式传递数据，主要用于更新bitmap类型的数据)
* @param bitmap
* @param positon
*/
public void sendPic(Bitmap bitmap, int positon) {
Message msg = new Message();
msg.what = 0;
List list = new ArrayList();
list.add(bitmap);
msg.obj = list; //handler传递对象
msg.arg1 = positon;
handler.sendMessage(msg);
}
}
有了这个线程，就可以在适当的时候不耗时的状态下进行获取第一帧。
接下来就是数据库的创建
/**
* 数据库基础类，用于创建数据库
**/
public class DbHelper extends SQLiteOpenHelper {
private static final String name = "your dbName"; //数据库名称
private static final int version = 1; //数据库版本
public DbHelper(Context context) {
super(context, name, null, version);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("CREATE TABLE IF NOT EXISTS "+ "your table name"+" (id integer primary key autoincrement, name text, imgurl text, videourl text)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
}
}
/**
* 数据库工具类
*/
public class DbManager {
private BaisongDbHelper dbHelper;
private SQLiteDatabase db;
public static int dbSize = 0;
public DbManager(Context context) {
dbHelper = new BaisongDbHelper(context);
db = dbHelper.getReadableDatabase();
}
/**
* 添加图片到数据库
*/
public void addMustImage(String video_url, String image_url) {
if (find_video_url(video_url)!=null){
updateMustVideo(video_url);
return;
}
if (find_image_url(image_url)!=null){
updateMustImage(video_url,image_url);
return;
}
ContentValues cv = new ContentValues();
cv.put("videourl", video_url);
cv.put("imgurl", image_url);
long id = db.insert(ConfigYibaisong.MUST_IMAGE, null, cv);//插入数据库
//--------以下是利用数组打印插入数据的代码--------------
Cursor cursor = db.query(ConfigYibaisong.MUST_IMAGE, null, "videourl=?" + " and " + "imgurl=?", new String[]{video_url, image_url}, null, null, null);
ArrayList<HashMap<String, String>> AL = new ArrayList<HashMap<String, String>>();
if (cursor.moveToNext()) {
for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
HashMap<String, String> hm = new HashMap<>();
hm.put("videourl", cursor.getString(cursor.getColumnIndex("videourl")));
hm.put("imgurl", cursor.getString(cursor.getColumnIndex("imgurl")));
AL.add(hm);
}
cursor.close();
}
if (id != -1) Log.d("zzzzzzzzz", "插入成功 " + AL.toString());
else Log.d("zzzzzzzzz", "插入失败");
// db.close();
// db.insert(ConfigYibaisong.MUST_IMAGE, null, cv);
}
/**
* 更新图片
*/
public void updateMustVideo(String video_url){
ContentValues cv = new ContentValues();
cv.put("videourl", video_url);
long id = db.update(ConfigYibaisong.MUST_IMAGE, cv,"videourl=?",new String[]{video_url});//插入数据库
if (id != -1) LogHelper.d("zzzzzzzzz", "更新成功 ");
else LogHelper.d("zzzzzzzzz", "更新失败");
}
/**
* 更新图片
*/
public void updateMustImage(String video_url,String image_url){
ContentValues cv = new ContentValues();
cv.put("imgurl", image_url);
long id = db.update(ConfigYibaisong.MUST_IMAGE, cv,"videourl=?",new String[]{video_url});//插入数据库
if (id != -1) Log.d("zzzzzzzzz", "更新成功 ");
else Log.d("zzzzzzzzz", "更新失败");
}
/**
* 查找video地址
*/
public String find_video_url(String video_url){
Cursor cursor = db.query(ConfigYibaisong.MUST_IMAGE, null, "videourl=?" , new String[]{video_url}, null, null, null);
if (cursor.moveToNext()) {
for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
return cursor.getString(cursor.getColumnIndex("videourl"));
}
cursor.close();
}
return null;
}
/**
* 查找图片地址
*/
public String find_image_url(String image_url){
Cursor cursor = db.query(ConfigYibaisong.MUST_IMAGE, null, "imgurl=?" , new String[]{image_url}, null, null, null);
if (cursor.moveToNext()) {
for (cursor.moveToFirst(); !cursor.isAfterLast(); cursor.moveToNext()) {
return cursor.getString(cursor.getColumnIndex("imgurl"));
}
cursor.close();
}
return null;
}
public void DbClose() {
db.close();
}
public long getCount() {
return db.getMaximumSize();
}
/**
* 根据给定video地址查询本地图片地址
*/
public String findMustImage(int position, String video_url, String image_url) {
if (TextUtils.isEmpty(video_url) || TextUtils.isEmpty(image_url))
return "";
if (tabbleIsExist(db, ConfigYibaisong.MUST_IMAGE)) {
Cursor cursor = db.query(ConfigYibaisong.MUST_IMAGE, null, "videourl=?" + " and " + "imgurl=?", new String[]{video_url, image_url}, null, null, null);
String cursorStr = "";
try {
cursorStr = cursor.getString(cursor.getColumnIndex("imgurl"));
cursor.close();
} catch (CursorIndexOutOfBoundsException e) {
cursorStr = null;
}
return cursorStr;
// }
}
return null;
}
/**
* 根据给定video地址查询本地图片地址
*/
public String findMustImage(String video_url) {
if (TextUtils.isEmpty(video_url))
return "";
if (tabbleIsExist(db, ConfigYibaisong.MUST_IMAGE)) {
Cursor cursor = db.query(ConfigYibaisong.MUST_IMAGE, new String[]{"imgurl"}, "videourl=?", new String[]{video_url}, null, null, null);
String cursorStr = "";
if(cursor.moveToNext()){
try {
cursorStr = cursor.getString(0);
cursor.close();
return cursorStr;
} catch (CursorIndexOutOfBoundsException e) {
cursorStr = null;
}
return cursorStr;
}
// }
}
return null;
}
public List<NewMustClassBean.DataBean> findAllImageForMustCover(List<NewMustClassBean.DataBean> mDatas) {
for (int i = 0; i < mDatas.size(); i++) {
try {
Cursor cursor = db.query(ConfigYibaisong.MUST_IMAGE, new String[]{"imgurl"}, "videourl=?", new String[]{mDatas.get(i).getVideo()}, null, null, null);
mDatas.get(i).setVideoCover(cursor.getString(cursor.getColumnIndex("imgurl")));
} catch (CursorIndexOutOfBoundsException e) {
return mDatas;
}
}
return mDatas;
}
/**
* 根据给定video地址查询本地图片地址
*/
public void findImageMustCover(String videourl,List<NewMustClassBean.DataBean> mDatas,int position) {
try {
List<NewMustClassBean.DataBean> mMusts = new ArrayList<>();
Cursor cursor = db.query(ConfigYibaisong.MUST_IMAGE, new String[]{"imgurl"}, "videourl=?", new String[]{videourl}, null, null, null);
while (cursor.moveToNext()) {
NewMustClassBean.DataBean bean = new NewMustClassBean.DataBean();
bean.setVideoCover(cursor.getString(cursor.getColumnIndex("imgurl")));
mMusts.add(bean);
}
mDatas.get(position).setVideoCover(mMusts.get(position).getVideoCover());
} catch (CursorIndexOutOfBoundsException e) {
}
}
//删除某一个表
public void dropTable() {
db.delete(ConfigYibaisong.MUST_IMAGE, null, null);
}
//判断一个表是否存在
public boolean tabbleIsExist(SQLiteDatabase db, String tableName) {
boolean result = false;
if (tableName == null) {
return false;
}
Cursor cursor = null;
try {
String sql = "select count(*) as c from Sqlite_master where type ='table' and name ='" + tableName.trim() + "' ";
cursor = db.rawQuery(sql, null);
if (cursor.moveToNext()) {
int count = cursor.getInt(0);
if (count > 0) {
result = true;
}
}
} catch (Exception e) {
// TODO: handle exception
}
return result;
}
}
创建完数据库，接下来就是把图片存入内存，拿到地址，放到数据库，以方便对本地图片的取出加载。
/**
* 保存图片到本地
**/
public class PictureUtils {
public static final String POSTFIX = ".jpeg";
public static String saveImageToSD(Bitmap bmp, String dirPath) {
if (bmp == null) {
return "";
}
File appDir = new File(dirPath);
if (!appDir.exists()) {
appDir.mkdir();
}
String fileName = System.currentTimeMillis() + ".jpg";
File file = new File(appDir, fileName);
try {
FileOutputStream fos = new FileOutputStream(file);
bmp.compress(Bitmap.CompressFormat.JPEG, 100, fos);
fos.flush();
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
return file.getAbsolutePath();
}
public static String saveImageToSDForEdit(Bitmap bmp, String dirPath, String fileName) {
if (bmp == null) {
return "";
}
File appDir = new File(dirPath);
if (!appDir.exists()) {
appDir.mkdir();
}
File file = new File(appDir, fileName);
if (file.exists()){
return file.getAbsolutePath();
}
try {
FileOutputStream fos = new FileOutputStream(file);
bmp.compress(Bitmap.CompressFormat.JPEG, 80, fos);
fos.flush();
fos.close();
} catch (IOException e) {
e.printStackTrace();
return "null";
}
return file.getAbsolutePath();
}
public static void deleteFile(File f) {
if (f.isDirectory()) {
File[] files = f.listFiles();
if (files != null && files.length > 0) {
for (int i = 0; i < files.length; ++i) {
deleteFile(files[i]);
}
}
}
f.delete();
}
}
保存完图片了，也建立了数据库了，那接下来就是把图片地址存到数据库，并在第二次开启时取出本地图片，利用glide加载到界面上就行了。再贴一个handler吧，用于更新获取完第一帧，实时更新UI的过程。
/**
* 在更新UI的方法
*/
private Handler handler = new Handler() {
public void handleMessage(Message msg) {
switch (msg.what) {
case 0: //接到从线程内传来的图片bitmap和imageView.
//这里只是将bitmap传到imageView中就行了。只所以不在线程中做是考虑到线程的安全性
mDatas.get(msg.arg1).setmVideoCover("file://" + msg.obj);
try {
if (!TextUtils.equals(mDatas.get(msg.arg1).getmVideoCover(), "file://null"))
manager.addImage(mDatas.get(msg.arg1));
}catch (Exception ex){
}
notifyItemChanged(msg.arg1);
// notifyDataSetChanged();
break;
default:
super.handleMessage(msg);
break;
}
}
;
};
当然别忘了添加网络请求和动态请求读写的使用权限~。
希望这个思路能对大家有所帮助。
