Go语言视频零基础入门到精通

卡卡的梦

和Image，Audio一样，在Android中，Video信息也被MediaStore管理着。
和每个视频对应的有其一个缩略图，这个缩略图往往是其第一帧的图像。
下面看代码：
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package demo.camera;
import java.util.ArrayList;
import java.util.List;
import android.app.ListActivity;
import android.content.Context;
import android.database.Cursor;
import android.net.Uri;
import android.os.Bundle;
import android.provider.MediaStore;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.BaseAdapter;
import android.widget.ImageView;
import android.widget.TextView;
/**
* 本实例，我们将通过检索SDCard上的Video信息
* 在MediaStore中，MediaStore.Video.Media中就有Video相关信息，
* 同时MediaStore.Video.Thumbnails中含有各个video对应的缩略图信息
*
* @author Administrator
*
*/
public class AdvancedVideoDemo extends ListActivity {

private Cursor cursor;

public void onCreate(Bundle savedInstanceState){
super.onCreate(savedInstanceState);
setContentView(R.layout.video_advanced);

init();
}


private void init(){
String[] thumbColumns = new String[]{
MediaStore.Video.Thumbnails.DATA,
MediaStore.Video.Thumbnails.VIDEO_ID
};

String[] mediaColumns = new String[]{
MediaStore.Video.Media.DATA,
MediaStore.Video.Media._ID,
MediaStore.Video.Media.TITLE,
MediaStore.Video.Media.MIME_TYPE
};

//首先检索SDcard上所有的video
cursor = this.managedQuery(MediaStore.Video.Media.EXTERNAL_CONTENT_URI, mediaColumns, null, null, null);

ArrayList<VideoInfo> videoList = new ArrayList<AdvancedVideoDemo.VideoInfo>();

if(cursor.moveToFirst()){
do{
VideoInfo info = new VideoInfo();

info.filePath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.DATA));
info.mimeType = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.MIME_TYPE));
info.title = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Media.TITLE));

//获取当前Video对应的Id，然后根据该ID获取其Thumb
int id = cursor.getInt(cursor.getColumnIndexOrThrow(MediaStore.Video.Media._ID));
String selection = MediaStore.Video.Thumbnails.VIDEO_ID +"=?";
String[] selectionArgs = new String[]{
id+""
};
Cursor thumbCursor = this.managedQuery(MediaStore.Video.Thumbnails.EXTERNAL_CONTENT_URI, thumbColumns, selection, selectionArgs, null);

if(thumbCursor.moveToFirst()){
info.thumbPath = cursor.getString(cursor.getColumnIndexOrThrow(MediaStore.Video.Thumbnails.DATA));

}

//然后将其加入到videoList
videoList.add(info);

}while(cursor.moveToNext());
}

//然后需要设置ListView的Adapter了，使用我们自定义的Adatper
VideoAdapter adapter = new VideoAdapter(this, videoList);
this.getListView().setAdapter(adapter);
}

static class VideoInfo{
String filePath;
String mimeType;
String thumbPath;
String title;
}

/**
* 定义一个Adapter来显示缩略图和视频title信息
* @author Administrator
*
*/
static class VideoAdapter extends BaseAdapter{

private Context context;
private List<VideoInfo> videoItems;

public VideoAdapter(Context context, List<VideoInfo> data){
this.context = context;
this.videoItems = data;
}
@Override

public int getCount() {
// TODO Auto-generated method stub
return videoItems.size();
}
@Override

public Object getItem(int p) {
// TODO Auto-generated method stub
return videoItems.get(p);
}
@Override

public long getItemId(int p) {
// TODO Auto-generated method stub
return p;
}
@Override

public View getView(int position, View convertView, ViewGroup parent) {
ViewHolder holder = null;
if(convertView == null){
holder = new ViewHolder();
convertView = LayoutInflater.from(context).inflate(R.layout.video_item, null);
holder.thumbImage = (ImageView)convertView.findViewById(R.id.thumb_image);
holder.titleText = (TextView)convertView.findViewById(R.id.video_title);
convertView.setTag(holder);
}else{
holder = (ViewHolder)convertView.getTag();
}

//显示信息
holder.titleText.setText(videoItems.get(position).title);
if(videoItems.get(position).thumbPath != null){
holder.thumbImage.setImageURI(Uri.parse(videoItems.get(position).thumbPath));
}

return convertView;
}

class ViewHolder{
ImageView thumbImage;
TextView titleText;
}

}
}