新手求教。。有关onPreviewFrame未被调用的问题

2013-06-15 10:20:48 581 阅读 AI 写同款 · GEO 优化AI 选题数据监测一键分发 ›

android相机如何只显示处理后的图像以及这里onPreviewFrame不被调用的原因前段时间，一直想写一个关于android相机的程序，阅读详情

在写一个简单的通过onPreviewFrame获取摄像头当前预览的图像再发送出去的程序。
但是运行的时候发现完全就没有调用这个函数。
用debug逐步调试的时候发现走到
camera.setPreviewCallback(MainActivity.this);这句就直接跳到设置变量的Camera camera;这句话然后就没有了。。。完全没有调用onPreviewFrame这个函数

网上有人说用了surfaceholder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);就无法调用onPreviewFrame。但是在eclipse里面那段代码提醒说是deprecated。

我去掉这条代码（应该是不能去掉的吧？）就直接程序崩坏。
究竟是怎么回事呀，各位求方法。求解答啊。
怎么才可以调用这个onPreviewFrame呢

...全文

在onPreviewFrame中获取图片在onPreviewFrame中获取图片在onPreviewFrame获取帧图片 byte[]转bitmap的坑 &amp;gt; 有个需求，要求在扫码页做到拍照的操作，满心欢喜的onPreviewFrame-&amp;gt;decodeByteArray(data) -&amp;gt;savaBitmap，完成，突如其来的告诉我bitmap==null，但是进行扫码处理是正常的，数据源没有问题，搜了很久，... 阅读详情

wuheng0316

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QQ515311445 2015-06-25

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我的也是, DEBUG时就调用了, push到系统中就没调用, 不知道啥原因

老样子AAAA 2013-11-12

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使用到MediaRecorder时需要camera.unlock();导致了onPreviewFrame（）不会被调用到，所以在录制视频时不能同时形成帧图片，我现在也是这个问题想要同时录制视频和形成帧图片，如果楼主解决了，能联系一下我吗？求提示帮忙

happy08god 2013-07-12

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不知道在SurfaceChanged 里面是否能去处理。。后面我试试看。。

happy08god 2013-07-11

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我也遇到了。。囧

look_down 2013-07-09

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问题解决没？我也遇到啦！

wuheng0316 2013-06-16

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求助啊。。。纠结啦好几天了啊

wuheng0316 2013-06-16

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没人啊。。。纠结了好几天了。。帮帮忙嘛各位大大

wuheng0316 2013-06-15

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代码


package com.example.testfordraw;

  


import java.io.ByteArrayInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.IOException;

import javax.security.auth.callback.Callback;



import android.app.Activity;  
import android.content.Context;  
import android.content.pm.ActivityInfo;
import android.graphics.Canvas;  
import android.graphics.Color;  
import android.graphics.Paint;  
import android.graphics.PixelFormat;
import android.graphics.Rect;  
import android.graphics.YuvImage;
import android.hardware.Camera;
import android.hardware.Camera.Size;
import android.media.MediaRecorder;
import android.os.Bundle;  
import android.os.Environment;
import android.util.AttributeSet;
import android.view.Menu;
import android.view.SurfaceHolder;  
import android.view.SurfaceView;  
import android.view.View;
import android.view.Window;
import android.view.WindowManager;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.Toast;
public class MainActivity extends Activity implements SurfaceHolder.Callback,Camera.PreviewCallback{

	private Camera camera;
	public static ByteArrayOutputStream outputstream = null;
	private SurfaceView msurfaceview;
	private Button buttonstart;
	private Button buttonstop;
	private MediaRecorder recorder;
	private SurfaceHolder surfaceholder;
	private File savefile;
	private File SDfile;
	private String savepath;
	private File recfile;
	private int Width = 320;
	private int Height = 240;
	private boolean isRecording = false ;
	private boolean istrans = false ;
	private int videoformat=0;
	private int VideoQuality=85;
	private float VideoWidthRatio=1;
	 private float VideoHeightRatio=1;
		private String username= "wh";
	
	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		requestWindowFeature(Window.FEATURE_NO_TITLE);
		getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,WindowManager.LayoutParams.FLAG_FULLSCREEN);
		getWindow().setFormat(PixelFormat.TRANSLUCENT);
		setRequestedOrientation(ActivityInfo.SCREEN_ORIENTATION_LANDSCAPE); 
		setContentView(R.layout.activity_main);
		msurfaceview = (SurfaceView) findViewById(R.id.mysurfaceview);
		buttonstart = (Button) findViewById(R.id.start);
		SDfile = Environment.getExternalStorageDirectory();
		savepath = SDfile.getAbsolutePath()+File.separator+"mvideo"+File.separator;
		savefile = new File(savepath);
		buttonstart.setText("start");
		buttonstart.setOnClickListener(new buttonstartlistener());

		
		
		if (!savefile.exists())
		{
			savefile.mkdirs();
		}
				
}
	class buttonstartlistener implements OnClickListener{

		@Override
		public void onClick(View v) {
			// TODO Auto-generated method stub
			if(istrans==false)
			{
				//record();
				istrans = true;
				camera.setPreviewCallback(MainActivity.this);
			}else{
				//Stoprecording();
				istrans =false;
			}
			if(istrans == false)
			{
				buttonstart.setText("start");
			}else{
				buttonstart.setText("stop");
			}
		}
		
	}
	public void Stoprecording() {




			if(recorder!= null){
				recorder.stop();
				recorder.reset();
				recorder.release();
				recorder = null;
				isRecording = false ;
				}
			try{
				camera.reconnect();
			}catch(IOException e ){
				Toast.makeText(this, "reconect fail", 0).show();
				e.printStackTrace();
			}
		}
		

	public void record()
	{
		try{
			
			camera.unlock();
			isRecording = true ;
			recorder = new MediaRecorder();
			recfile = File.createTempFile("Video",".3gp",savefile);
			recorder.setCamera(camera);
			recorder.reset();
			recorder.setCamera(camera);			
			recorder.setVideoSource(MediaRecorder.VideoSource.CAMERA);
			recorder.setAudioSource(MediaRecorder.AudioSource.MIC);
			recorder.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
			recorder.setVideoEncoder(MediaRecorder.VideoEncoder.H264);
			recorder.setOutputFile(recfile.getAbsolutePath());
			recorder.setVideoSize(320,480);
			recorder.setVideoFrameRate(20);
			recorder.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
			recorder.setPreviewDisplay(surfaceholder.getSurface());
			recorder.prepare();
			recorder.start();
		}catch(IOException e){
			e.printStackTrace();
		}
	}

	@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;
	}


	@Override
	public void onPreviewFrame(byte[] data, Camera camera) {
		// TODO Auto-generated method stub
		if(istrans == false){
			return;
		}
		if(data!=null)
		{
			try{
				YuvImage image = new YuvImage(data, videoformat, Width, Height, null);
				if(image!=null){
					 ByteArrayOutputStream outstream = new  ByteArrayOutputStream();
					 Rect rect = new Rect(0,0,(int)(VideoWidthRatio*Width),(int)(VideoHeightRatio*Height));
					 image.compressToJpeg(rect, VideoQuality, outstream);
					 outputstream = outstream;
					 outstream.flush();

				}
			}catch(Exception e){}
		}
	}


	

		@Override
		public void surfaceChanged(SurfaceHolder holder, int format,
				int width, int height) {
			if(camera != null){
				return;
			}
			camera.stopPreview();
			camera.setPreviewCallback(MainActivity.this);
			
			Camera.Parameters parameters = camera.getParameters();
			Size size = parameters.getPreviewSize();
			Width = size.width;
			Height = size.height;
			videoformat = parameters.getPreviewFormat();
			camera.startPreview();
			// TODO Auto-generated method stub
			
		}

	
		@Override
		protected void onStart() {
			// TODO Auto-generated method stub
			surfaceholder = msurfaceview.getHolder();
			surfaceholder.addCallback(this);
			surfaceholder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);	
			VideoWidthRatio=VideoWidthRatio/100f;
		    VideoHeightRatio=VideoHeightRatio/100f;
			super.onStart();
		}


		@Override
		public void surfaceCreated(SurfaceHolder holder) {
			camera = Camera.open();
			try{
				camera.setPreviewDisplay(surfaceholder);
			}catch (IOException e){
				e.printStackTrace();
			}
			camera.startPreview();
			Camera.Parameters parameters = camera.getParameters();
			Size size = parameters.getPreviewSize();
			Width = size.width;
			Height = size.height;
			videoformat = parameters.getPreviewFormat();


		}

		@Override
		public void surfaceDestroyed(SurfaceHolder holder) {
			if(camera !=null){
				camera.setPreviewCallback(null);
				camera.stopPreview();
				camera.release();
				camera = null;
			}				
		}
		

	
}

为什么别人的都可以调用，就我的不行呢。。camera.setPreviewCallback有写啊

新手求教。。有关onPreviewFrame未被调用的问题

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