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Android ViewPager中顯示圖片與播放視頻的填坑記錄

更新時(shí)間：2018年05月04日 09:31:08 作者：Android-劉旭

這篇文章主要給介紹了關(guān)于Android ViewPager中顯示圖片與播放視頻的一些填坑記錄，文中通過示例代碼介紹的非常詳細(xì)，對(duì)各位Android開發(fā)者們具有一定的參考學(xué)習(xí)價(jià)值，需要的朋友們下面隨著小編來一起學(xué)習(xí)學(xué)習(xí)吧。

ViewPager介紹

ViewPager的功能就是可以使視圖滑動(dòng)，就像Lanucher左右滑動(dòng)那樣。

ViewPager用于實(shí)現(xiàn)多頁面的切換效果，該類存在于Google的兼容包android-support-v4.jar里面.

ViewPager:

1)ViewPager類直接繼承了ViewGroup類，所有它是一個(gè)容器類，可以在其中添加其他的view類。

2)ViewPager類需要一個(gè)PagerAdapter適配器類給它提供數(shù)據(jù)。

3)ViewPager經(jīng)常和Fragment一起使用，并且提供了專門的FragmentPagerAdapter和FragmentStatePagerAdapter類供Fragment中的ViewPager使用。

4)在編寫ViewPager的應(yīng)用的使用，還需要使用兩個(gè)組件類分別是PagerTitleStrip類和PagerTabStrip類，PagerTitleStrip類直接繼承自ViewGroup類，而PagerTabStrip類繼承PagerTitleStrip類，所以這兩個(gè)類也是容器類。但是有一點(diǎn)需要注意，在定義XML的layout 的時(shí)候，這兩個(gè)類必須是ViewPager標(biāo)簽的子標(biāo)簽，不然會(huì)出錯(cuò)。

本文將詳細(xì)介紹關(guān)于Android ViewPager中顯示圖片與播放視頻填坑的相關(guān)內(nèi)容，分享出來供大家參考學(xué)習(xí)，下面話不多說了，來一起看看詳細(xì)的介紹吧。

一.需求來源與實(shí)現(xiàn)思路

1.最近項(xiàng)目需求中有用到需要在ViewPager中播放視頻和顯示圖片的功能，視頻是本地視頻，最開始的實(shí)現(xiàn)思路是ViewPager中根據(jù)當(dāng)前item位置對(duì)應(yīng)的是圖片還是視頻去初始化PhotoView和SurfaceView，同時(shí)銷毀時(shí)根據(jù)item的位置去判斷移除PhotoView和SurfaceView。

2.上面那種方式確實(shí)是可以實(shí)現(xiàn)的，但是存在2個(gè)問題，第一，MediaPlayer的生命周期不容易控制并且存在內(nèi)存泄漏問題。第二，連續(xù)三個(gè)item都是視頻時(shí)，來回滑動(dòng)的過程中發(fā)現(xiàn)會(huì)出現(xiàn)上個(gè)視頻的最后一幀畫面的bug。

3.未提升用戶體驗(yàn)，視頻播放器初始化完成前上面會(huì)覆蓋有該視頻的第一幀圖片,但是發(fā)現(xiàn)存在第一幀圖片與視頻第一幀信息不符的情況，后面會(huì)通過代碼給出解決方案。

4.圖片和視頻尺寸如何適配以保證不變形。

二.需要填的坑

1.對(duì)于MediaPlayer的生命周期不容易控制的本質(zhì)原因是這種實(shí)現(xiàn)思路上我的播放器只有1個(gè)，頻繁的初始化和銷毀造成了問題，所以后面我更改了實(shí)現(xiàn)方式，一個(gè)item的視頻對(duì)應(yīng)一個(gè)播放器。

2.對(duì)于滑動(dòng)過程中發(fā)現(xiàn)會(huì)出現(xiàn)上個(gè)視頻的最后一幀畫面的bug,發(fā)現(xiàn)是surfaceView這個(gè)控件造成的，后面通過將播放的載體更換為TextureView完美解決該問題。

3.SurfaceView與TextureView的本質(zhì)異同

第一：兩者都能在獨(dú)立的線程中繪制和渲染，在專用的GPU線程中大大提高渲染的性能。

第二：SurfaceView專門提供了嵌入視圖層級(jí)的繪制界面，開發(fā)者可以控制該界面像Size等的形式，能保證界面在屏幕上的正確位置。但也有局限：
1.由于是獨(dú)立的一層View，更像是獨(dú)立的一個(gè)Window，不能加上動(dòng)畫、平移、縮放；
2.兩個(gè)SurfaceView不能相互覆蓋。

第三:Texture更像是一般的View，像TextView那樣能被縮放、平移，也能加上動(dòng)畫。TextureView只能在開啟了硬件加速的Window中使用，并且消費(fèi)的內(nèi)存要比SurfaceView多，并伴隨著1-3幀的延遲。

第四:屏幕鎖屏?xí)rSurfaceView會(huì)銷毀重建，TextureView不會(huì)！

三.具體實(shí)現(xiàn)核心代碼

1.ViewPager的初始化

mAdapter = ImageBrowseFragmentPagerAdapter(supportFragmentManager, this, imgs)
 imgs_viewpager.offscreenPageLimit = 1
 imgs_viewpager.adapter = mAdapter
 imgs_viewpager.currentItem = mPosition


 //為了處理首次點(diǎn)擊時(shí)視頻播放的問題
 val message = Message.obtain()
 message.what = START_PLAY_VIDEO
 mHandler.sendMessageDelayed(message, 200)

2.Handler處理消息

private val START_PLAY_VIDEO = 0
private var DELETE_VIDEO = 1
private var DELETE_VIDEO_START_PLAY = 2
private var mHandler = Handler(Handler.Callback { msg ->
  when (msg.what) {
   //開始播放視頻
   START_PLAY_VIDEO -> NotifyDispatch.dispatch(PreviewPlayVideoEvent(mPosition))
   //刪除視頻時(shí)刷新ui
   DELETE_VIDEO -> {
    mAdapter?.setImgs(imgs)
   }
   //解決刪除視頻時(shí)之后跳轉(zhuǎn)到另一個(gè)item,當(dāng)它是視頻時(shí)不繼續(xù)播放的問題
   DELETE_VIDEO_START_PLAY -> NotifyDispatch.dispatch(PreviewPlayVideoEvent(mDeletePosition))
  }
  true
 })

3.刪除視頻或圖片的處理邏輯

 private fun deletePhotos(position: Int) {
  if (imgs!!.isEmpty()) {
   return
  }
  ThreadDispatch.right_now.execute({
   var file: File?
   file = File(imgs.get(position))
   if (file != null && file?.exists()!!) {
    val intent = Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE)
    val uri = Uri.fromFile(file)
    intent.data = uri
    sendBroadcast(intent)
    file?.delete()
    imgs.removeAt(position)
   }


   if (position == imgs.size) {
    mDeletePosition = position - 1
   } else {
    mDeletePosition = position
   }
   val message = Message.obtain()
   message.what = DELETE_VIDEO
   mHandler.sendMessage(message)
   NotifyDispatch.dispatch(DeletePreviewPhotoEvent(imgs))
   val message1 = Message.obtain()
   message1.what = DELETE_VIDEO_START_PLAY
   mHandler.sendMessageDelayed(message1, 200)
   if (imgs.isEmpty()) {
    finish()
   }
  })
// }
 }

4.ViewPager對(duì)應(yīng)的Adapter

package com.immomo.camerax.gui.view.adapter;
import android.content.Context;
import android.os.Bundle;
import android.support.v4.app.Fragment;
import android.support.v4.app.FragmentManager;
import android.support.v4.app.FragmentStatePagerAdapter;
import android.support.v4.app.FragmentTransaction;
import android.view.View;
import android.view.ViewGroup;
import com.immomo.camerax.gui.fragment.PreviewImgFragment;
import com.immomo.camerax.gui.fragment.PreviewVideoFragment;
import java.util.ArrayList;
import java.util.List;

/**
 * Created by liuxu on 2018/3/26.
 */

public class ImageBrowseFragmentPagerAdapter extends FragmentStatePagerAdapter {
 private Context mContext;
 private List<String> datas;
 private int mCurrentSelectedPosition = -1;
 private FragmentManager mFragmentManager;
 private FragmentTransaction mFragmentTransaction;
 private ArrayList<Fragment> mFragments = new ArrayList<>();

 public ImageBrowseFragmentPagerAdapter(FragmentManager fm, Context context, List<String> datas) {
  super(fm);
  mFragmentManager = fm;
  mContext = context;
  this.datas = datas;
 }

 public void removeContext(){
  mContext = null;
 }

 @Override
 public void setPrimaryItem(ViewGroup container, int position, Object object) {
  mCurrentSelectedPosition = position;
 }

 @Override
 public void startUpdate(ViewGroup container) {
  super.startUpdate(container);
 }

 public void setImgs(List<String> imgs) {
  this.datas = imgs;
  notifyDataSetChanged();
 }

 //處理更新無效----刪除條目
 @Override
 public int getItemPosition(Object object) {
  return POSITION_NONE;
 }

 public int getPrimaryItemPosition() {
  return mCurrentSelectedPosition;
 }

 public ImageBrowseFragmentPagerAdapter(FragmentManager fm) {
  super(fm);
 }

 @Override
 public boolean isViewFromObject(View view, Object object) {
  return view == ((Fragment) object).getView();
 }

 @Override
 public Fragment getItem(int position) {
  Bundle bundle = new Bundle();
  bundle.putString("url", datas.get(position));
  bundle.putInt("position", position);
  if (datas.get(position).endsWith(".jpg")) {
   PreviewImgFragment previewImgFragment = new PreviewImgFragment();
   previewImgFragment.setArguments(bundle);
   return previewImgFragment;
  } else {
   PreviewVideoFragment previewVideoFragment = new PreviewVideoFragment();
   previewVideoFragment.setArguments(bundle);
   return previewVideoFragment;
  }
 }

 @Override
 public int getCount() {
  return datas == null ? 0 : datas.size();
 }

 @Override
 public Object instantiateItem(ViewGroup container, int position) {
  return super.instantiateItem(container,position);
 }

 @Override
 public void destroyItem(ViewGroup container, int position, Object object) {
  super.destroyItem(container,position,object);
 }
}

5顯示圖片對(duì)應(yīng)的Fragment

package com.immomo.camerax.gui.fragment;
import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import com.bumptech.glide.Glide;
import com.immomo.camerax.R;
import com.immomo.camerax.foundation.util.StatusBarUtils;
import com.immomo.camerax.gui.view.ResizablePhotoView;
/**
 * Created by liuxu on 2018/3/27.
 */
public class PreviewImgFragment extends Fragment {
 @Nullable
 @Override
 public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
  View view = inflater.inflate(R.layout.fragment_preview_photo, null);
  ResizablePhotoView resizablePhotoView = view.findViewById(R.id.customPhotoView);
  String url = getArguments().getString("url");
  Glide.with(getContext()).load(url).into(resizablePhotoView);
  resizablePhotoView.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {
    getActivity().finish();
   }
  });
  return view;
 }

 @Override
 public void onPause() {
  super.onPause();
 }

 @Override
 public void onResume() {
  super.onResume();
 }

 @Override
 public void onDetach() {
  super.onDetach();
 }

 @Override
 public void onDestroyView() {
  super.onDestroyView();
 }

 @Override
 public void onStart() {
  super.onStart();
 }

 @Override
 public void onDestroy() {
  super.onDestroy();
 }

 @Override
 public void setUserVisibleHint(boolean isVisibleToUser) {
  super.setUserVisibleHint(isVisibleToUser);
 }
}

6.圖片根據(jù)寬度適配高度的自定義View

package com.immomo.camerax.gui.view;
import android.content.Context;
import android.graphics.drawable.Drawable;
import android.util.AttributeSet;
import com.github.chrisbanes.photoview.PhotoView;

/**
 * Created by liuxu on 2018/4/7.
 */

public class ResizablePhotoView extends PhotoView {
 public ResizablePhotoView(Context context) {
  super(context);
 }

 public ResizablePhotoView(Context context, AttributeSet attr) {
  super(context, attr);
 }

 public ResizablePhotoView(Context context, AttributeSet attr, int defStyle) {
  super(context, attr, defStyle);
 }

 @Override
 protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
  Drawable d = getDrawable();
  if (d != null){
   int width = MeasureSpec.getSize(widthMeasureSpec);
   //高度根據(jù)使得圖片的寬度充滿屏幕計(jì)算而得
   int height = (int) Math.ceil((float) width * (float) d.getIntrinsicHeight() / (float) d.getIntrinsicWidth());
   setMeasuredDimension(width, height);
  }else {
   super.onMeasure(widthMeasureSpec, heightMeasureSpec);
  }
 }
}

7.播放視頻對(duì)應(yīng)的Fragment

/**
 * Created by liuxu on 2018/3/27.
 */

public class PreviewVideoFragment extends Fragment {
 private ImageView mPhotoView;
 private TextureView mTextureView;
 private String mUrl;
 private int mPosition;
 private AndroidMediaPlayer mIjkVodMediaPlayer;
 private boolean mIsSelected;
 private boolean mIsFirstPrepared;
 private PreviewPlayVideoSubscriber mPreviewPlayVideoSubscriber = new PreviewPlayVideoSubscriber() {
  @Override
  public void onEventMainThread(PreviewPlayVideoEvent event) {
   super.onEventMainThread(event);
   MDLog.e("liuxu",event.getPosition()+"");
   if (event != null && event.getPosition() == mPosition) {
    //說明是當(dāng)前條目
    if (mIjkVodMediaPlayer != null && !mIjkVodMediaPlayer.isPlaying()) {
     if (mTextureView != null) {
      mIjkVodMediaPlayer.setSurface(mSurface);
      mIjkVodMediaPlayer.prepareAsync();
      mPhotoView.setVisibility(View.VISIBLE);
     }
    }
    mIsSelected = true;
   } else {
    if (mIjkVodMediaPlayer != null && mIjkVodMediaPlayer.isPlaying()) {
     mIjkVodMediaPlayer.pause();
     mIjkVodMediaPlayer.stop();
    }

    if (mPhotoView != null) {
     mPhotoView.setVisibility(View.VISIBLE);
    }
    mIsSelected = false;
   }

  }
 };
 private String mWidth;
 private String mHeight;

 @Nullable
 @Override
 public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
  mPreviewPlayVideoSubscriber.register();
  View view = inflater.inflate(R.layout.fragment_preview_video, null);
  mPhotoView = view.findViewById(R.id.photoView);
  mTextureView = view.findViewById(R.id.surfaceView);
  mUrl = getArguments().getString("url");
  mPosition = getArguments().getInt("position");
  layoutPlayer();
  loadVideoScreenshot(getContext(), mUrl, mPhotoView, 1);
  view.setOnClickListener(new View.OnClickListener() {
   @Override
   public void onClick(View view) {

    release();
    getActivity().finish();
   }
  });
  initTextureMedia();
  return view;
 }

 private void initTextureMedia() {
  mTextureView.setSurfaceTextureListener(mSurfaceTextureListener);
 }

 private void play(String url) {
  try {
   mIjkVodMediaPlayer = new AndroidMediaPlayer();
   mIjkVodMediaPlayer.reset();
   mIjkVodMediaPlayer.setDataSource(url);
   //讓MediaPlayer和TextureView進(jìn)行視頻畫面的結(jié)合
   mIjkVodMediaPlayer.setSurface(mSurface);
   //設(shè)置監(jiān)聽
   mIjkVodMediaPlayer.setOnBufferingUpdateListener((mp, percent) -> {

   });
   mIjkVodMediaPlayer.setOnCompletionListener(mp -> {
    mp.seekTo(0);
    mp.start();
   });
   mIjkVodMediaPlayer.setOnInfoListener((mp1, what, extra) -> {
      if (what == IMediaPlayer.MEDIA_INFO_VIDEO_RENDERING_START) {
       mPhotoView.setVisibility(View.GONE);
       mIsFirstPrepared = true;
      }
      return false;
     });
   mIjkVodMediaPlayer.setOnErrorListener((mp, what, extra) -> false);
   mIjkVodMediaPlayer.setOnPreparedListener(mp -> {
    mp.start();
    if (!mIsFirstPrepared){
    }else {
     mPhotoView.setVisibility(View.GONE);
    }
   });
   mIjkVodMediaPlayer.setScreenOnWhilePlaying(true);//在視頻播放的時(shí)候保持屏幕的高亮
   if (mIsSelected){
    //異步準(zhǔn)備
    mIjkVodMediaPlayer.prepareAsync();
   }
  } catch (Exception e) {
   e.printStackTrace();
  }
 }

 private Surface mSurface;
 private TextureView.SurfaceTextureListener mSurfaceTextureListener = new TextureView.SurfaceTextureListener() {
  @Override
  public void onSurfaceTextureAvailable(SurfaceTexture surface, int width, int height) {
   mSurface = new Surface(surface);
   play(mUrl);
  }

  @Override
  public void onSurfaceTextureSizeChanged(SurfaceTexture surface, int width, int height) {

  }

  @Override
  public boolean onSurfaceTextureDestroyed(SurfaceTexture surface) {
   if (mSurface != null){
    mSurface.release();
    mSurface = null;
   }
   if (mTextureView != null){
    if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
     mTextureView.releasePointerCapture();
    }
   }
   release();
   return false;
  }
  @Override
  public void onSurfaceTextureUpdated(SurfaceTexture surface) {

  }
 };


 @Override
 public void onStart() {
  super.onStart();
 }
 @Override
 public void onAttach(Context context) {
  super.onAttach(context);
 }

 @Override
 public void onDetach() {
  super.onDetach();
 }

 @Override
 public void onPause() {
  MDLog.e("liuxu", "onPause" + mPosition);
  //處理鎖屏?xí)r播放器停止播放
  if (mIjkVodMediaPlayer != null && mIjkVodMediaPlayer.isPlaying()){
   mIjkVodMediaPlayer.pause();
   mIjkVodMediaPlayer.stop();
  }
  super.onPause();
 }

 //屏幕打開時(shí)重新播放
 @Override
 public void onResume() {
  MDLog.e("liuxu", "onResume" + mPosition);
  super.onResume();
  if (mIsSelected && mIjkVodMediaPlayer != null && !mIjkVodMediaPlayer.isPlaying()) {
   mIjkVodMediaPlayer.prepareAsync();
  }
 }

 @Override
 public void onDestroy() {
  MDLog.e("liuxu", "onDestroy");
  release();
  if (mPreviewPlayVideoSubscriber.isRegister()) {
   mPreviewPlayVideoSubscriber.unregister();
  }
  super.onDestroy();
 }

 private void release() {
  if (mIjkVodMediaPlayer == null) {
   return;
  }
  if (mIjkVodMediaPlayer.isPlaying()) {
   mIjkVodMediaPlayer.stop();
  }
  mIjkVodMediaPlayer.release();
  mIjkVodMediaPlayer = null;
 }

 @Override
 public boolean getUserVisibleHint() {
  return super.getUserVisibleHint();
 }

 /**
  * 動(dòng)態(tài)設(shè)置視頻寬高信息
  */
 private void layoutPlayer() {
  //獲取視頻寬高比
  getPlayInfo(mUrl);
  float ratio = Float.parseFloat(mHeight) / Float.parseFloat(mWidth);
  MDLog.e("type", mPosition + "ratio" + ratio);
  int type = 0;
  //添加容錯(cuò)值
  if (ratio < MediaConstants.INSTANCE.getASPECT_RATIO_1_1().toFloat() + MediaConstants.INSTANCE.getSCREEN_DEFAULT_VALUE()
    && ratio > MediaConstants.INSTANCE.getASPECT_RATIO_1_1().toFloat() - MediaConstants.INSTANCE.getSCREEN_DEFAULT_VALUE()) {
   type = ScreenAdapterUtils.INSTANCE.getSCALE_TYPE_11();
  } else if (ratio < MediaConstants.INSTANCE.getASPECT_RATIO_4_3().toFloat() + MediaConstants.INSTANCE.getSCREEN_DEFAULT_VALUE()
    && ratio > MediaConstants.INSTANCE.getASPECT_RATIO_4_3().toFloat() - MediaConstants.INSTANCE.getSCREEN_DEFAULT_VALUE()) {
   type = ScreenAdapterUtils.INSTANCE.getSCALE_TYPE_43();
   MDLog.e("type", "43");
  } else if (ratio < MediaConstants.INSTANCE.getASPECT_RATIO_16_9().toFloat() + MediaConstants.INSTANCE.getSCREEN_DEFAULT_VALUE()
    && ratio > MediaConstants.INSTANCE.getASPECT_RATIO_16_9().toFloat() - MediaConstants.INSTANCE.getSCREEN_DEFAULT_VALUE()) {
   type = ScreenAdapterUtils.INSTANCE.getSCALE_TYPE_169();
   MDLog.e("type", "169");
  }

  FrameLayout.LayoutParams layoutParams = (FrameLayout.LayoutParams) mTextureView.getLayoutParams();
  layoutParams.height = ScreenAdapterUtils.INSTANCE.getSurfaceHeight(type);
  mTextureView.setLayoutParams(layoutParams);
  FrameLayout.LayoutParams params = (FrameLayout.LayoutParams) mPhotoView.getLayoutParams();
  params.height = ScreenAdapterUtils.INSTANCE.getSurfaceHeight(type);
  mPhotoView.setLayoutParams(params);
  MDLog.e("params.height", params.height + "");
 }


 private void getPlayInfo(String mUri) {
  android.media.MediaMetadataRetriever mmr = new android.media.MediaMetadataRetriever();
  try {
   if (mUri != null) {
    mmr.setDataSource(mUri);
   } else {
    //mmr.setDataSource(mFD, mOffset, mLength);
   }

   //寬
   mWidth = mmr.extractMetadata(android.media.MediaMetadataRetriever.METADATA_KEY_VIDEO_WIDTH);
   //高
   mHeight = mmr.extractMetadata(android.media.MediaMetadataRetriever.METADATA_KEY_VIDEO_HEIGHT);
//   mBitmap = mmr.getFrameAtTime(1 );

  } catch (Exception ex) {
  } finally {
   mmr.release();
  }

 }

 public static void loadVideoScreenshot(final Context context, String uri, ImageView imageView, long frameTimeMicros) {
  // 這里的時(shí)間是以微秒為單位
  RequestOptions requestOptions = RequestOptions.frameOf(frameTimeMicros);
  requestOptions.set(FRAME_OPTION, MediaMetadataRetriever.OPTION_CLOSEST);
  requestOptions.transform(new BitmapTransformation() {
   @Override
   protected Bitmap transform(@NonNull BitmapPool pool, @NonNull Bitmap toTransform, int outWidth, int outHeight) {
    return toTransform;
   }

   @Override
   public void updateDiskCacheKey(MessageDigest messageDigest) {
    try {
     messageDigest.update((context.getPackageName() + "RotateTransform").getBytes("utf-8"));
    } catch (Exception e) {
     e.printStackTrace();
    }
   }
  });
  Glide.with(context).load(uri).apply(requestOptions).into(imageView);
 }
}

4.結(jié)語

筆者使用這種方式實(shí)現(xiàn)了項(xiàng)目需求，但是由于本人接觸音視頻的相關(guān)內(nèi)容比較少，全是在不斷探索和學(xué)習(xí)中前進(jìn)，如有不足之處請(qǐng)?jiān)u論指正，謝謝。大家共同學(xué)習(xí)共同進(jìn)步。

好了以上就是這篇文章的全部?jī)?nèi)容了，希望本文的內(nèi)容對(duì)大家的學(xué)習(xí)或者工作具有一定的參考學(xué)習(xí)價(jià)值，如果有疑問大家可以留言交流，謝謝大家對(duì)腳本之家的支持。

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