VideoView可双指缩放大小的视频播放研究

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实际上，VideoView播放和可缩放之间没有任何必然联系。奈何由着我性子来（实际上是突然发现了可以这样试试）。依旧没有GIF图。依旧仅仅作为技术积累研究。

功能点：
横竖屏切换记录播放进度
跳转页面返回，或者切换后台再进来记录播放顺讯。
双指自由缩放视频播放大小。

原始大小：

缩放大小：

下面贴代码：

MainActivity.java

package com.example.qxb_810.videoplaydemo;

import android.Manifest;
import android.content.pm.PackageManager;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v4.app.ActivityCompat;
import android.support.v7.app.AppCompatActivity;
import android.view.MotionEvent;
import android.view.View;
import android.widget.LinearLayout;
import android.widget.MediaController;
import android.widget.VideoView;

import butterknife.BindView;
import butterknife.ButterKnife;

public class MainActivity extends AppCompatActivity {

    @BindView(R.id.vv_video)
    VideoView vvVideo;

    private int mCurrPostion = 0;
    private double mCurrDistance = 0;
    private double mlastDistance = 0;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        ButterKnife.bind(this);
        requestPermissions();
        if (savedInstanceState != null) {
            // 横竖屏切换重新创建时获取播放进度
            mCurrPostion = savedInstanceState.getInt("currPostion", 0);
        }
        initVideo();
        initEvent();
    }

    /**
     * 动态申请权限  ----  API23后需要动态申请权限
     */
    private void requestPermissions() {
        if (ActivityCompat.checkSelfPermission(this, Manifest.permission.WRITE_EXTERNAL_STORAGE) != PackageManager.PERMISSION_GRANTED) {
            // 读写存储权限 和联网权限
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.WRITE_EXTERNAL_STORAGE}, 1);
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.READ_EXTERNAL_STORAGE}, 1);
            ActivityCompat.requestPermissions(this, new String[]{Manifest.permission.INTERNET}, 1);
        }
    }

    @Override
    protected void onSaveInstanceState(Bundle outState) {
        outState.putInt("currPostion", vvVideo.getCurrentPosition());
        super.onSaveInstanceState(outState);
    }

    private void initVideo() {
        // 互联网路径 : http://****.***
        Uri uri = Uri.parse(Environment.getExternalStorageDirectory().getPath() + "/bluetooth/pfzl.mp4");//将路径转换成uri
        vvVideo.setMediaController(new MediaController(MainActivity.this));//显示控制进度条
        vvVideo.setVideoURI(uri);//为视频播放器设置视频路径
        vvVideo.seekTo(mCurrPostion);
        vvVideo.start();
    }

    private void initEvent() {
        vvVideo.setOnTouchListener(new View.OnTouchListener() {
            @Override
            public boolean onTouch(View v, MotionEvent event) {
                switch (event.getAction()) {
                    case MotionEvent.ACTION_UP:
                        mlastDistance = 0;
                        mCurrDistance = 0;
                        break;

                    case MotionEvent.ACTION_DOWN:
                        // 点击播放或暂停
                        if (vvVideo.isPlaying()) {
                            mCurrPostion = vvVideo.getCurrentPosition();
                            vvVideo.pause();
                        } else {
                            vvVideo.seekTo(mCurrPostion);
                            vvVideo.start();
                        }
                }

                // 实现缩放效果
                if (event.getPointerCount() >= 2) {
                    float offsetX = event.getX(0) - event.getX(1);
                    float offsetY = event.getY(0) - event.getY(1);
                    mCurrDistance = Math.sqrt(offsetX * offsetX + offsetY * offsetY);
                    // 说明刚开始还未赋值
                    if (mlastDistance == 0) {
                        mlastDistance = mCurrDistance;
                    } else {
                        // 改变幅度大于5时
                        if (Math.abs(mCurrDistance - mlastDistance) > 5) {
                            LinearLayout.LayoutParams layoutParams = (LinearLayout.LayoutParams) vvVideo.getLayoutParams();
                            layoutParams.width = vvVideo.getWidth() + (int) (mCurrDistance - mlastDistance);
                            layoutParams.height = vvVideo.getHeight() + (int) (mCurrDistance - mlastDistance);
                            vvVideo.setLayoutParams(layoutParams);
                            mlastDistance = mCurrDistance;
                        }
                    }
                }

                return true;
            }
        });


    }

    @Override
    protected void onStop() {
        super.onStop();
        if (vvVideo.isPlaying()) {
            mCurrPostion = vvVideo.getCurrentPosition();
            vvVideo.pause();
        }
    }

    @Override
    protected void onRestart() {
        super.onRestart();
        vvVideo.seekTo(mCurrPostion);
        vvVideo.start();
    }
}

对应布局文件：

<?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"
    android:gravity="center">

    <LinearLayout
        android:gravity="center"
        android:layout_width="match_parent"
        android:layout_height="match_parent">
        <VideoView
            android:id="@+id/vv_video"
            android:layout_width="500dp"
            android:layout_height="400dp"
            android:layout_gravity="center" />
    </LinearLayout>
</LinearLayout>