视频直播开篇之camera+TextureSurface预览

今天来讲讲使用camera接口和TextureSurface两个来进行预览

先看xml：

<?xml version="1.0" encoding="utf-8"?>
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".camera_texture_activity">
<TextureView
    android:id="@+id/preview_textureview"
    android:layout_width="match_parent"
    android:layout_height="match_parent" />
</android.support.constraint.ConstraintLayout>

xml里面就只有一个TextureView,这个就是用来预览的控件。

再看代码的实现：

package com.example.amei.cameraexample;

import android.graphics.SurfaceTexture;
import android.hardware.Camera;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.TextureView;

public class camera_texture_activity extends AppCompatActivity implements TextureView.SurfaceTextureListener {
    private static final String TAG = "cameraTexture";
    private TextureView mTextureView = null;
    private Camera mCamera = null;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_camera_texture_activity);
        mTextureView = findViewById(R.id.preview_textureview);


        mCamera = Camera.open(0);
        mTextureView.setSurfaceTextureListener(this);
    }

    @Override
    public void onSurfaceTextureAvailable(SurfaceTexture surfaceTexture, int i, int i1) {
        try{
            mCamera.setPreviewTexture(surfaceTexture);
            mCamera.startPreview();
        }catch (Exception e)
        {

        }


    }

    @Override
    public void onSurfaceTextureSizeChanged(SurfaceTexture surfaceTexture, int i, int i1) {

    }

    @Override
    public boolean onSurfaceTextureDestroyed(SurfaceTexture surfaceTexture) {
        mCamera.release();
        return false;
    }

    @Override
    public void onSurfaceTextureUpdated(SurfaceTexture surfaceTexture) {

    }
}

代码里面首先是实例化camera接口，并且打开camera.设置TextureView的监听，这个监听是为了在合适的时间打开预览以及释放camera.从代码中可以看出在onSurfaceTextureAvailable里面首先将surfaceture设置给camera,然后再预览。这个和上一篇的suerface的显示很像，在上一篇中是设置SurfaceHolder，最终的目的其实都是将显示的数据画在surface上面。