VideoView 和 SurfaceView 实例

VideoView内部封装好了Mediaplayer.Android框架提供了VideoView类来封装MediaPalyer，这个VideoView类非常好用。Android自带的程序Gallery也是用VideoView实现的。相比之下，我们使用更方便
，实现MediaPlayer.OnCompletionListener接口，将会在Video播完的时候得到通知，本例只是简单的结束程序如下：

import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.pm.ActivityInfo;
import android.content.res.Configuration;
import android.media.AudioManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.os.Message;
import android.text.TextUtils;
import android.view.Display;
import android.view.GestureDetector.SimpleOnGestureListener;
import android.view.GestureDetector;
import android.view.MotionEvent;
import android.view.View;
import android.view.ViewGroup;
import android.view.WindowManager;
import android.widget.ImageView;

public class VideoPlayerActivity extends Activity implements OnCompletionListener {

private String mPath;
private String mTitle;
private VideoView mVideoView;
private View mVolumeBrightnessLayout;
private ImageView mOperationBg;
private ImageView mOperationPercent;
private AudioManager mAudioManager;
/** 最大声音 */
private int mMaxVolume;
/** 当前声音 */
private int mVolume = -1;
/** 当前亮度 */
private float mBrightness = -1f;
/** 当前缩放模式 */
private int mLayout = VideoView.VIDEO_LAYOUT_ZOOM;
private GestureDetector mGestureDetector;
private MediaController mMediaController;

@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);

Intent intent = getIntent();
mPath = intent.getStringExtra("path");
mTitle = intent.getStringExtra("title");
if (TextUtils.isEmpty(mPath))
mPath = Environment.getExternalStorageDirectory() + "/video/你太猖狂.flv";
else if (intent.getData() != null)
mPath = intent.getData().toString();

setContentView(R.layout.videoview);
mVideoView = (VideoView) findViewById(R.id.surface_view);
mVolumeBrightnessLayout = findViewById(R.id.operation_volume_brightness);
mOperationBg = (ImageView) findViewById(R.id.operation_bg);
mOperationPercent = (ImageView) findViewById(R.id.operation_percent);

mAudioManager = (AudioManager) getSystemService(Context.AUDIO_SERVICE);
mMaxVolume = mAudioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);
if (mPath.startsWith("http:"))
mVideoView.setVideoURI(Uri.parse(mPath));
else
mVideoView.setVideoPath(mPath);
//
mVideoView.setOnCompletionListener(this);

mMediaController = new MediaController(this);
//设置显示名称
mMediaController.setFileName(mTitle);
mVideoView.setMediaController(mMediaController);
mVideoView.requestFocus();

mGestureDetector = new GestureDetector(this, new MyGestureListener());

setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);
}

@Override
protected void onPause() {
super.onPause();
if (mVideoView != null)
mVideoView.pause();
}

@Override
protected void onResume() {
super.onResume();
if (mVideoView != null)
mVideoView.resume();
}

@Override
protected void onDestroy() {
super.onDestroy();
if (mVideoView != null)
mVideoView.stopPlayback();
}

@Override
public boolean onTouchEvent(MotionEvent event) {
if (mGestureDetector.onTouchEvent(event))
return true;

// 处理手势结束
switch (event.getAction() & MotionEvent.ACTION_MASK) {
case MotionEvent.ACTION_UP:
endGesture();
break;
}

return super.onTouchEvent(event);
}

/** 手势结束 */
private void endGesture() {
mVolume = -1;
mBrightness = -1f;

// 隐藏
mDismissHandler.removeMessages(0);
mDismissHandler.sendEmptyMessageDelayed(0, 500);
}

private class MyGestureListener extends SimpleOnGestureListener {

/** 双击 */
@Override
public boolean onDoubleTap(MotionEvent e) {
if (mLayout == VideoView.VIDEO_LAYOUT_ZOOM)
mLayout = VideoView.VIDEO_LAYOUT_ORIGIN;
else
mLayout++;
if (mVideoView != null)
mVideoView.setVideoLayout(mLayout, 0);
return true;
}

/** 滑动 */
@Override
public boolean onScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY) {
float mOldX = e1.getX(), mOldY = e1.getY();
int y = (int) e2.getRawY();
Display disp = getWindowManager().getDefaultDisplay();
int windowWidth = disp.getWidth();
int windowHeight = disp.getHeight();

if (mOldX > windowWidth * 4.0 / 5)// 右边滑动
onVolumeSlide((mOldY - y) / windowHeight);
else if (mOldX < windowWidth / 5.0)// 左边滑动
onBrightnessSlide((mOldY - y) / windowHeight);

return super.onScroll(e1, e2, distanceX, distanceY);
}
}

/** 定时隐藏 */
private Handler mDismissHandler = new Handler() {
@Override
public void handleMessage(Message msg) {
mVolumeBrightnessLayout.setVisibility(View.GONE);
}
};

/**
* 滑动改变声音大小
*
* @param percent
*/
private void onVolumeSlide(float percent) {
if (mVolume == -1) {
mVolume = mAudioManager.getStreamVolume(AudioManager.STREAM_MUSIC);
if (mVolume < 0)
mVolume = 0;

// 显示
mOperationBg.setImageResource(R.drawable.video_volumn_bg);
mVolumeBrightnessLayout.setVisibility(View.VISIBLE);
}

int index = (int) (percent * mMaxVolume) + mVolume;
if (index > mMaxVolume)
index = mMaxVolume;
else if (index < 0)
index = 0;

// 变更声音
mAudioManager.setStreamVolume(AudioManager.STREAM_MUSIC, index, 0);

// 变更进度条
ViewGroup.LayoutParams lp = mOperationPercent.getLayoutParams();
lp.width = findViewById(R.id.operation_full).getLayoutParams().width * index / mMaxVolume;
mOperationPercent.setLayoutParams(lp);
}

/**
* 滑动改变亮度
*
* @param percent
*/
private void onBrightnessSlide(float percent) {
if (mBrightness < 0) {
mBrightness = getWindow().getAttributes().screenBrightness;
if (mBrightness <= 0.00f)
mBrightness = 0.50f;
if (mBrightness < 0.01f)
mBrightness = 0.01f;

// 显示
mOperationBg.setImageResource(R.drawable.video_brightness_bg);
mVolumeBrightnessLayout.setVisibility(View.VISIBLE);
}
WindowManager.LayoutParams lpa = getWindow().getAttributes();
lpa.screenBrightness = mBrightness + percent;
if (lpa.screenBrightness > 1.0f)
lpa.screenBrightness = 1.0f;
else if (lpa.screenBrightness < 0.01f)
lpa.screenBrightness = 0.01f;
getWindow().setAttributes(lpa);

ViewGroup.LayoutParams lp = mOperationPercent.getLayoutParams();
lp.width = (int) (findViewById(R.id.operation_full).getLayoutParams().width * lpa.screenBrightness);
mOperationPercent.setLayoutParams(lp);
}

@Override
public void onConfigurationChanged(Configuration newConfig) {
if (mVideoView != null)
mVideoView.setVideoLayout(mLayout, 0);
super.onConfigurationChanged(newConfig);
}

@Override
public void onCompletion(MediaPlayer player) {
finish();
}
}

videoView 是android 系统提供的一个媒体播放显示和控制的控件。其结构层次如下：

　　原型：VideoView extends SurfaceView implements MediaController.MediaPlayerControl

　　类结构：

　　　　　　java.lang.Object

　　　　　　　　↳ android.view.View

　　　　　　　　　　↳ android.view.SurfaceView

　　　　　　　　　　　　↳ android.widget.VideoView

　　通过VideoView 的原型可知：如果构建更为复杂和有特色个性的视频View，需要继承SurfaceView 和实现MediaPlayerControl接口。其中SurfaceView 为显示提供支持，MediaPlayerControl则为媒体控制提供了支持。

核心播放类：

import android.app.Activity;
import android.os.Bundle;
import android.os.Environment;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

public class PlayerActivity extends Activity implements OnBufferingUpdateListener, OnCompletionListener, OnPreparedListener, OnVideoSizeChangedListener, SurfaceHolder.Callback {

private static final String TAG = "MediaPlayerDemo";
private int mVideoWidth;
private int mVideoHeight;
private MediaPlayer mMediaPlayer;
private SurfaceView mPreview;
private SurfaceHolder holder;
private String path = Environment.getExternalStorageDirectory() + "/Moon.mp4";

private boolean mIsVideoSizeKnown = false;
private boolean mIsVideoReadyToBePlayed = false;

@Override
public void onCreate(Bundle icicle) {
super.onCreate(icicle);
setContentView(R.layout.mediaplayer);
mPreview = (SurfaceView) findViewById(R.id.surface);
holder = mPreview.getHolder();
holder.addCallback(this);
}

private void playVideo() {
doCleanUp();
try {
mMediaPlayer = new MediaPlayer(this);
mMediaPlayer.setDataSource(path);
mMediaPlayer.setDisplay(holder);
mMediaPlayer.prepareAsync();
mMediaPlayer.setScreenOnWhilePlaying(true);
mMediaPlayer.setOnBufferingUpdateListener(this);
mMediaPlayer.setOnCompletionListener(this);
mMediaPlayer.setOnPreparedListener(this);
mMediaPlayer.setOnVideoSizeChangedListener(this);
} catch (Exception e) {
Log.e(TAG, "error: " + e.getMessage(), e);
}
}

@Override
public void onBufferingUpdate(MediaPlayer arg0, int percent) {
Log.d(TAG, "onBufferingUpdate percent:" + percent);

}

@Override
public void onCompletion(MediaPlayer arg0) {
Log.d(TAG, "onCompletion called");
mMediaPlayer.release();
}

@Override
public void onVideoSizeChanged(MediaPlayer mp, int width, int height) {
Log.v(TAG, "onVideoSizeChanged called");
if (width == 0 || height == 0) {
Log.e(TAG, "invalid video width(" + width + ") or height(" + height + ")");
return;
}
mIsVideoSizeKnown = true;
mVideoWidth = width;
mVideoHeight = height;
if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
startVideoPlayback();
}
}

@Override
public void onPrepared(MediaPlayer mediaplayer) {
Log.d(TAG, "onPrepared called");
mIsVideoReadyToBePlayed = true;
if (mIsVideoReadyToBePlayed && mIsVideoSizeKnown) {
startVideoPlayback();
}
}

@Override
public void surfaceChanged(SurfaceHolder surfaceholder, int i, int j, int k) {
Log.d(TAG, "surfaceChanged called" + i + "  " + j + "   " + k);
}

@Override
public void surfaceDestroyed(SurfaceHolder surfaceholder) {
Log.d(TAG, "surfaceDestroyed called");
}

@Override
public void surfaceCreated(SurfaceHolder holder) {
Log.d(TAG, "surfaceCreated called");
playVideo();
}

@Override
protected void onPause() {
super.onPause();
releaseMediaPlayer();
doCleanUp();
}

@Override
protected void onDestroy() {
super.onDestroy();
releaseMediaPlayer();
doCleanUp();
}

private void releaseMediaPlayer() {
if (mMediaPlayer != null) {
mMediaPlayer.release();
mMediaPlayer = null;
}
}

private void doCleanUp() {
mVideoWidth = 0;
mVideoHeight = 0;
mIsVideoReadyToBePlayed = false;
mIsVideoSizeKnown = false;
}

private void startVideoPlayback() {
Log.v(TAG, "startVideoPlayback");
holder.setFixedSize(mVideoWidth, mVideoHeight);
mMediaPlayer.start();
}
}