有哪些做特卖的网站/seo的工作原理

安卓系统提供了VideoView用来播放一些特定格式的视频，与MediaController结合使用可以对视频播放进行简单控制
例如：
在布局文件中先声明个VideoView：

<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android"android:id="@+id/content_main2"android:layout_width="match_parent"android:layout_height="match_parent"><VideoViewandroid:id="@+id/videoView"android:layout_width="match_parent"android:layout_height="wrap_content" /></RelativeLayout>

然后，在存储卡的根目录下先放置一个命名为“00.MP4”的视频文件

@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main2);VideoView videoView = (VideoView) findViewById(R.id.videoView);MediaController mediaController = new MediaController(this);videoView.setMediaController(mediaController);mediaController.setMediaPlayer(videoView);//为videoView设置视频路径String path = Environment.getExternalStorageDirectory().getAbsolutePath();videoView.setVideoPath(path + "/00.mp4");}

播放效果如下：

这里写图片描述

这里再来自定义视频播放控制界面与控制逻辑，增添音量调节，亮度调节，沉浸式状态栏等功能

竖屏状态效果如下：

这里写图片描述

横屏状态下效果如下：

这里写图片描述

首先要先设计布局样式

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"android:layout_width="match_parent"android:layout_height="match_parent"android:orientation="vertical"><RelativeLayoutandroid:id="@+id/rl_video"android:layout_width="match_parent"android:layout_height="240dp"><VideoViewandroid:id="@+id/vv_player"android:layout_width="match_parent"android:layout_height="240dp" /><LinearLayoutandroid:id="@+id/ll_control"android:layout_width="match_parent"android:layout_height="wrap_content"android:layout_alignBottom="@id/vv_player"android:background="#8768423e"android:orientation="vertical"><SeekBarandroid:id="@+id/sb_play"android:layout_width="match_parent"android:layout_height="wrap_content"android:indeterminate="false" /><RelativeLayoutandroid:layout_width="match_parent"android:layout_height="wrap_content"android:gravity="center_horizontal"><LinearLayoutandroid:id="@+id/ll_playControl"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginBottom="5dp"android:layout_marginLeft="5dp"android:gravity="center"android:orientation="horizontal"><ImageViewandroid:id="@+id/iv_playControl"android:layout_width="wrap_content"android:layout_height="wrap_content"android:clickable="true"android:src="@drawable/play_btn_style" /><TextViewandroid:id="@+id/tv_currentTime"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginLeft="7dp"android:text="00:00:00"android:textColor="#ffffff"android:textSize="15sp" /><TextViewandroid:layout_width="wrap_content"android:layout_height="wrap_content"android:text=" / "android:textColor="#ffffff"android:textSize="15sp" /><TextViewandroid:id="@+id/tv_totalTime"android:layout_width="wrap_content"android:layout_height="wrap_content"android:text="00:00:00"android:textColor="#ef6363"android:textSize="15sp" /></LinearLayout><ImageViewandroid:id="@+id/iv_screenSwitch"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_alignParentRight="true"android:layout_marginRight="5dp"android:src="@drawable/full_screen" /><LinearLayoutandroid:id="@+id/ll_volumeControl"android:layout_width="wrap_content"android:layout_height="wrap_content"android:layout_marginRight="10dp"android:layout_toLeftOf="@id/iv_screenSwitch"android:gravity="end"android:orientation="horizontal"android:visibility="gone"><ImageViewandroid:id="@+id/iv_volume"android:layout_width="wrap_content"android:layout_height="wrap_content"android:src="@drawable/volume" /><SeekBarandroid:id="@+id/sb_volume"android:layout_width="150dp"android:layout_height="wrap_content"android:indeterminate="false" /></LinearLayout></RelativeLayout></LinearLayout></RelativeLayout><ListViewandroid:layout_width="match_parent"android:layout_height="wrap_content" /></LinearLayout>

id为“ll_control”的LinearLayout包含了所有的控制View，将之置于VideoView上且设置半透明背景色，音量调节seekBar在竖屏状态下不可见

主要代码如下：
初始化UI

private void initUI() {videoView = (VideoView) findViewById(R.id.vv_player);sb_play = (SeekBar) findViewById(R.id.sb_play);sb_volume = (SeekBar) findViewById(R.id.sb_volume);iv_playControl = (ImageView) findViewById(R.id.iv_playControl);iv_screenSwitch = (ImageView) findViewById(R.id.iv_screenSwitch);iv_volume = (ImageView) findViewById(R.id.iv_volume);tv_currentTime = (TextView) findViewById(R.id.tv_currentTime);tv_totalTime = (TextView) findViewById(R.id.tv_totalTime);ll_volumeControl = (LinearLayout) findViewById(R.id.ll_volumeControl);ll_control = (LinearLayout) findViewById(R.id.ll_control);rl_video = (RelativeLayout) findViewById(R.id.rl_video);sb_volume.setMax(audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC));sb_volume.setProgress(audioManager.getStreamVolume(AudioManager.STREAM_MUSIC));}

初始化各种事件

private void initEvent() {iv_playControl.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if (videoView.isPlaying()) {setPauseStatus();videoView.pause();uiHandler.removeMessages(UPDATE_TIME);} else {setPlayStatus();videoView.start();uiHandler.sendEmptyMessage(UPDATE_TIME);}}});sb_play.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {@Overridepublic void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {if (fromUser) {videoView.seekTo(progress);Utils.updateTimeFormat(tv_currentTime, progress);}}@Overridepublic void onStartTrackingTouch(SeekBar seekBar) {uiHandler.removeMessages(UPDATE_TIME);if (!videoView.isPlaying()) {setPlayStatus();videoView.start();}}@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {uiHandler.sendEmptyMessage(UPDATE_TIME);}});sb_volume.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {@Overridepublic void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, progress, 0);}@Overridepublic void onStartTrackingTouch(SeekBar seekBar) {}@Overridepublic void onStopTrackingTouch(SeekBar seekBar) {}});videoView.setOnCompletionListener(new MediaPlayer.OnCompletionListener() {@Overridepublic void onCompletion(MediaPlayer mp) {iv_playControl.setImageResource(R.drawable.play_btn_style);videoView.seekTo(0);sb_play.setProgress(0);Utils.updateTimeFormat(tv_currentTime, 0);videoView.pause();uiHandler.removeMessages(UPDATE_TIME);}});iv_screenSwitch.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View v) {if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_LANDSCAPE) {setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_PORTRAIT);iv_screenSwitch.setImageResource(R.drawable.exit_full_screen);} else if (getResources().getConfiguration().orientation == Configuration.ORIENTATION_PORTRAIT) {setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE);iv_screenSwitch.setImageResource(R.drawable.full_screen);}}});videoView.setOnTouchListener(this);}

在横屏和竖屏切换时，会回调以下方法

public void onConfigurationChanged(Configuration newConfig)

在此要对View的大小进行调整以适应屏幕

@Overridepublic void onConfigurationChanged(Configuration newConfig) {super.onConfigurationChanged(newConfig);screenWidth = getResources().getDisplayMetrics().widthPixels;screenHeight = getResources().getDisplayMetrics().heightPixels;if (newConfig.orientation == Configuration.ORIENTATION_LANDSCAPE) {setSystemUiHide();setVideoViewScale(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);iv_screenSwitch.setImageResource(R.drawable.exit_full_screen);ll_volumeControl.setVisibility(View.VISIBLE);} else if (newConfig.orientation == Configuration.ORIENTATION_PORTRAIT) {setVideoViewScale(ViewGroup.LayoutParams.MATCH_PARENT, Utils.dp2px(MainActivity.this, 240f));iv_screenSwitch.setImageResource(R.drawable.full_screen);ll_volumeControl.setVisibility(View.GONE);setSystemUiVisible();}}

View大小调节

 /*** 设置布局大小** @param width  宽度* @param height 高度*/private void setVideoViewScale(int width, int height) {ViewGroup.LayoutParams params = rl_video.getLayoutParams();params.width = width;params.height = height;rl_video.setLayoutParams(params);ViewGroup.LayoutParams layoutParams = videoView.getLayoutParams();layoutParams.width = width;layoutParams.height = height;videoView.setLayoutParams(layoutParams);}

此外，为了使视频在全屏播放时更加和谐，调用以下方法对系统状态栏和虚拟按键进行隐藏与显示

private void setSystemUiHide() {if (Build.VERSION.SDK_INT >= 19) {View decorView = getWindow().getDecorView();decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_LAYOUT_STABLE| View.SYSTEM_UI_FLAG_LAYOUT_HIDE_NAVIGATION| View.SYSTEM_UI_FLAG_LAYOUT_FULLSCREEN| View.SYSTEM_UI_FLAG_HIDE_NAVIGATION| View.SYSTEM_UI_FLAG_FULLSCREEN| View.SYSTEM_UI_FLAG_IMMERSIVE_STICKY);}}private void setSystemUiVisible() {if (Build.VERSION.SDK_INT >= 19) {View decorView = getWindow().getDecorView();decorView.setSystemUiVisibility(View.SYSTEM_UI_FLAG_VISIBLE);}}

此外，通过手势识别可以对亮度和音量进行调节

private void changeVolume(float offset) {int maxVolume = audioManager.getStreamMaxVolume(AudioManager.STREAM_MUSIC);int currentVolume = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);int index = (int) (offset / screenHeight * maxVolume);int volume = Math.max(currentVolume + index, 0);volume = Math.min(volume, maxVolume);audioManager.setStreamVolume(AudioManager.STREAM_MUSIC, volume, 0);sb_volume.setProgress(volume);}private void changeBrightness(float offset) {WindowManager.LayoutParams attributes = getWindow().getAttributes();float brightness = attributes.screenBrightness;float index = offset / screenHeight / 2;brightness = Math.max(brightness + index, WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_OFF);brightness = Math.min(WindowManager.LayoutParams.BRIGHTNESS_OVERRIDE_FULL, brightness);attributes.screenBrightness = brightness;getWindow().setAttributes(attributes);}

关于手势识别 OnGestureListener的使用在我的上一篇博客也介绍过了

此外，为了使seekBar的进度能够在用户通过音量键调节音量时也能自动变化，需要再加上一个广播接收器

/*** 音量变化广播接收器* Created by CZY on 2017/1/31.*/
public class VolumeReceiver extends BroadcastReceiver {private ImageView iv_volume;private SeekBar seekBar_volume;/*** 音频管理器*/private AudioManager audioManager;public VolumeReceiver(Context context, ImageView iv_volume, SeekBar seekBar_volume) {this.iv_volume = iv_volume;this.seekBar_volume = seekBar_volume;audioManager = (AudioManager) context.getSystemService(Context.AUDIO_SERVICE);}@Overridepublic void onReceive(Context context, Intent intent) {if (intent.getAction().equals("android.media.VOLUME_CHANGED_ACTION")) {int volume = audioManager.getStreamVolume(AudioManager.STREAM_MUSIC);if (volume == 0) {iv_volume.setImageResource(R.drawable.mute);} else {iv_volume.setImageResource(R.drawable.volume);}seekBar_volume.setProgress(volume);}}}

为了在屏幕切换时可以不重新创建Activity而只是回调onConfigurationChanged 函数，可以为Activity增添以下属性

android:configChanges="orientation|screenSize|keyboard|keyboardHidden"

且程序要读取存储卡文件，需要申请权限

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

代码中使用到的图标我都是从一个公开图标库中下载的，个人感觉还是挺不错的
网址：http://iconfont.cn/collections

这里也提高源代码下载：简单定制一个视频播放器