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📜  Android-TextureView

📅  最后修改于: 2021-01-05 05:36:20             🧑  作者: Mango

如果要显示实时视频流或任何内容流，例如视频或OpenGL场景，则可以使用android提供的TextureView来做到这一点。

为了使用TextureView，您需要做的就是获取它的SurfaceTexture.SurfaceTexture然后可以用来渲染内容。为此，您只需要实例化此类的对象并实现SurfaceTextureListener接口。其语法如下-

private TextureView myTexture;
public class MainActivity extends Activity implements SurfaceTextureListener{
   protected void onCreate(Bundle savedInstanceState) {
      myTexture = new TextureView(this);
      myTexture.setSurfaceTextureListener(this);
      setContentView(myTexture);
   }
}

之后，您需要做的就是重写其方法。方法列出如下-

@Override
public void onSurfaceTextureAvailable(SurfaceTexture arg0, int arg1, int arg2) {
}

@Override
public boolean onSurfaceTextureDestroyed(SurfaceTexture arg0) {
}

@Override
public void onSurfaceTextureSizeChanged(SurfaceTexture arg0, int arg1,int arg2) {
}

@Override
public void onSurfaceTextureUpdated(SurfaceTexture arg0) {
}

通过使用setAlpha和setRotation方法，可以旋转纹理视图中显示的任何视图，并可以调整其alpha属性。其语法如下-

myTexture.setAlpha(1.0f);
myTexture.setRotation(90.0f);

除了这些方法，TextureView类中还有其他可用的方法。它们在下面列出-

Sr.No Method & description
1

getSurfaceTexture()

This method returns the SurfaceTexture used by this view.
2

getBitmap(int width, int height)

This method returns Returns a Bitmap representation of the content of the associated surface texture.
3

getTransform(Matrix transform)

This method returns the transform associated with this texture view.
4

isOpaque()

This method indicates whether this View is opaque.
5

lockCanvas()

This method start editing the pixels in the surface
6

setOpaque(boolean opaque)

This method indicates whether the content of this TextureView is opaque.
7

setTransform(Matrix transform)

This method sets the transform to associate with this texture view.
8

unlockCanvasAndPost(Canvas canvas)

This method finish editing pixels in the surface.

例

下面的示例演示TextureView类的用法。它创建了一个基本应用程序，可让您在纹理视图中查看相机并更改其角度，方向等

要尝试使用此示例，您需要在装有摄像头的实际设备上运行该示例。

Steps Description
1 You will use android studio IDE to create an Android application and name it as TextureView under a package com.example.textureview.
2 Modify src/MainActivity.java file to add Activity code.
3 Modify layout XML file res/layout/activity_main.xml add any GUI component if required.
5 Run the application and choose a running android device and install the application on it and verify the results.

这是src / com.example.textureview / MainActivity.java的内容。

package com.example.textureview;

import java.io.IOException;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.graphics.SurfaceTexture;
import android.hardware.Camera;
import android.os.Bundle;

import android.view.Gravity;
import android.view.Menu;
import android.view.TextureView;
import android.view.TextureView.SurfaceTextureListener;
import android.view.View;
import android.widget.FrameLayout;

public class MainActivity extends Activity implements SurfaceTextureListener {
   private TextureView myTexture;
   private Camera mCamera;

   @SuppressLint("NewApi")
   @Override
   protected void onCreate(Bundle savedInstanceState) {
      super.onCreate(savedInstanceState);
      setContentView(R.layout.activity_main);
      
      myTexture = new TextureView(this);
      myTexture.setSurfaceTextureListener(this);
      setContentView(myTexture);
   }
   
   @Override
   public boolean onCreateOptionsMenu(Menu menu) {
      // Inflate the menu; this adds items to the action bar if it is present.
      getMenuInflater().inflate(R.menu.main, menu);
      return true;
   }
   
   @SuppressLint("NewApi")
   @Override
   public void onSurfaceTextureAvailable(SurfaceTexture arg0, int arg1, int arg2) {
      mCamera = Camera.open();
      Camera.Size previewSize = mCamera.getParameters().getPreviewSize();
      
      myTexture.setLayoutParams(new FrameLayout.LayoutParams(
      previewSize.width, previewSize.height, Gravity.CENTER));
      
      try {
         mCamera.setPreviewTexture(arg0);
      } catch (IOException t) {
      }
        
      mCamera.startPreview();
      myTexture.setAlpha(1.0f);
      myTexture.setRotation(90.0f);
   }

   @Override
   public boolean onSurfaceTextureDestroyed(SurfaceTexture arg0) {
      mCamera.stopPreview();
      mCamera.release();
      return true;
   }

   @Override
   public void onSurfaceTextureSizeChanged(SurfaceTexture arg0, int arg1,
   int arg2) {
      // TODO Auto-generated method stub
   }
    
   @Override
   public void onSurfaceTextureUpdated(SurfaceTexture arg0) {
      // TODO Auto-generated method stub
   }
}

这是activity_main.xml的内容

这是AndroidManifest.xml的默认内容

让我们尝试运行TextureView应用程序。我假设您已将实际的Android Mobile设备与计算机连接。要从Android Studio运行该应用，请打开您项目的活动文件之一，然后点击运行Eclipse运行图标工具栏中的图标。在启动应用程序之前，Android Studio将显示以下窗口，以选择要在其中运行Android应用程序的选项。

Anroid TextureView教程

选择您的移动设备作为选项，然后检查将显示以下屏幕的移动设备。此屏幕的alpha属性设置为0.5 ，旋转设置为45。

Anroid TextureView教程

此屏幕的alpha属性设置为1.5 ，旋转设置为45 。

Anroid TextureView教程

此屏幕的alpha属性设置为1.0 ，旋转设置为90 。

Anroid TextureView教程