相机预览 - 姜饼

Question

以下代码适用于 froyo，我可以在姜饼上看到预览和记录屏幕是黑色的，直到您按下记录，它确实记录得很好，但预览不起作用

package com.exercise.AndroidVideoCapture;

import java.io.IOException;

import android.app.Activity;
import android.media.CamcorderProfile;
import android.media.MediaRecorder;
import android.os.Bundle;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.View;
import android.widget.Button;

public class AndroidVideoCapture extends Activity implements SurfaceHolder.Callback{

Button myButton;
MediaRecorder mediaRecorder;
SurfaceHolder surfaceHolder;
boolean recording;

/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    recording = false;

    mediaRecorder = new MediaRecorder();
    initMediaRecorder();

    setContentView(R.layout.main);

    SurfaceView myVideoView = (SurfaceView)findViewById(R.id.videoview);
    surfaceHolder = myVideoView.getHolder();
    surfaceHolder.addCallback(this);
    surfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);

    myButton = (Button)findViewById(R.id.mybutton);
    myButton.setOnClickListener(myButtonOnClickListener);
}

private Button.OnClickListener myButtonOnClickListener 
= new Button.OnClickListener(){

    @Override
    public void onClick(View arg0) {
        // TODO Auto-generated method stub
        if(recording){
            mediaRecorder.stop();
            mediaRecorder.release();
            finish();
        }else{
            mediaRecorder.start();
            recording = true;
            myButton.setText("STOP");
        }
    }};

@Override
public void surfaceChanged(SurfaceHolder arg0, int arg1, int arg2, int arg3) {
    // TODO Auto-generated method stub

}
@Override
public void surfaceCreated(SurfaceHolder arg0) {
    // TODO Auto-generated method stub
    prepareMediaRecorder();
}
@Override
public void surfaceDestroyed(SurfaceHolder arg0) {
    // TODO Auto-generated method stub

}

private void initMediaRecorder(){
    mediaRecorder.setAudioSource(MediaRecorder.AudioSource.DEFAULT);
    mediaRecorder.setVideoSource(MediaRecorder.VideoSource.DEFAULT);
    CamcorderProfile camcorderProfile_HQ = CamcorderProfile.get(CamcorderProfile.QUALITY_HIGH);
    mediaRecorder.setProfile(camcorderProfile_HQ);
    mediaRecorder.setOutputFile("/sdcard/myvideo.mp4");
    mediaRecorder.setMaxDuration(60000); // Set max duration 60 sec.
    mediaRecorder.setMaxFileSize(5000000); // Set max file size 5M
}

private void prepareMediaRecorder(){
    mediaRecorder.setPreviewDisplay(surfaceHolder.getSurface());
    try {
        mediaRecorder.prepare();
    } catch (IllegalStateException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    } catch (IOException e) {
        // TODO Auto-generated catch block
        e.printStackTrace();
    }
}
}

}

Answer 1

我这里也有同样的问题。
作为解决方法，如果 SDK 版本大于 8，我将调用 mediaRecorder.start()。
它很丑陋，可能不是最佳的，但我还没有找到更好的解决方案。

Answer 2

要在设置 MediaRecorder 之前查看相机预览，您必须打开 Camera 对象并开始预览。 MediaRecorder 也会执行此操作，但仅在您准备好之后，因此如果您在用户单击记录之前不调用该代码，您将只会看到一个空白屏幕。在这里查看简单的介绍：http: //integratingstuff.com/2010/10/18/writing-code-that-c​​aptures-videos-on-android/

您还可以浏览Android相机代码：
https://android.googlesource.com/platform/packages/apps/Camera