android 4.0 USB Camera实例(二)应用层

╰半橙微兮° 2022-08-25 15:48 176阅读 0赞

上一篇说了HAL层 这一篇具体应用HAL层 实例预览与拍照的功能

首先贴上两个主文件的源码

Fimcgzsd.java

package com.dao.usbcam;
    
    public class Fimcgzsd {
    	static public native int open(byte[] devname);
    	static public native int qbuf(int index);
    	static public native int streamon();
    	static public native int streamoff();
    	static public native int dqbuf(byte[] videodata);
    	static public native int release();
    	static public native int init(int width, int height,int numbuf);
    	static {
    		System.loadLibrary("fimcgzsd");
    	}
    }

这个主要是HAL层的一些接口函数

MainActivity.java

package com.dao.usbcam;
    
    import java.io.File;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    
    import android.app.Activity;
    import android.graphics.Bitmap;
    import android.graphics.BitmapFactory;
    import android.os.Bundle;
    import android.os.Environment;
    import android.os.Handler;
    import android.text.format.Time;
    import android.view.Menu;
    import android.view.View;
    import android.view.Window;
    import android.view.WindowManager;
    import android.view.View.OnClickListener;
    import android.widget.Button;
    import android.widget.ImageView;
    import android.widget.Toast;
    
    public class MainActivity extends Activity {
    	private ImageView mImag;
    	private int width = 640;
    	private int height = 480;
    	private String devname = "/dev/video3";
    	private byte[] mdata;
    	private Handler mHandler;
    	private int numbuf = 0;
    	private int index = 0;
    	private int ret = 0;
    	public Button mcap;
    	private Bitmap bitmap;
    	@Override
    	protected void onCreate(Bundle savedInstanceState) {
    		super.onCreate(savedInstanceState);
    		requestWindowFeature(Window.FEATURE_NO_TITLE);
    		getWindow().setFlags(WindowManager.LayoutParams.FLAG_FULLSCREEN,
    		  WindowManager.LayoutParams.FLAG_FULLSCREEN);
    		setContentView(R.layout.activity_main);
    		mImag = (ImageView)findViewById(R.id.mimg);
    		mcap = (Button)findViewById(R.id.mcap);
    		numbuf  = 4;
    		mdata = new byte[width * height * numbuf];
    		ret = Fimcgzsd.open(devname.getBytes());
    		if(ret < 0)
    			finish();
    		ret = Fimcgzsd.init(width, height, numbuf);
    		if(ret < 0)
    			finish();
    		ret = Fimcgzsd.streamon();
    		if(ret < 0)
    			finish();
    		mHandler = new Handler();
    		new StartThread().start();
    		mcap.setOnClickListener(new CaptureListener());
    	}
    
    	final Runnable mUpdateUI = new Runnable() {
    
    		@Override
    		public void run() {
    			// TODO Auto-generated method stub
    			mImag.setImageBitmap(bitmap);
    		    
    		}
    	};
    	
    	class StartThread extends Thread {
    
    		@Override
    		public void run() {
    			// TODO Auto-generated method stub
    			//super.run();
    			while(true) {
    				index = Fimcgzsd.dqbuf(mdata);
    				if(index < 0) {
    					onDestroy();
    					break;
    				}
    				mHandler.post(mUpdateUI);
    				bitmap = BitmapFactory.decodeByteArray(mdata, 0, width * height);
    				Fimcgzsd.qbuf(index);
    			}
    		}
    
    	}
    	public static void saveMyBitmap(Bitmap mBitmap) {
        	Time mtime = new Time();
        	mtime.setToNow();
        	File fdir = new File(Environment.getExternalStorageDirectory().getPath() + "/DCIM/" + "/gzsd/");
        	if(!fdir.exists()) {
        		fdir.mkdir();
        	}
            File f = new File(Environment.getExternalStorageDirectory().getPath() + "/DCIM/" + "/gzsd/" + mtime.year + mtime.month + mtime.monthDay + mtime.hour + mtime.minute +mtime.second+".png");
            try {
                    f.createNewFile();
            } catch (IOException e) {
            	e.printStackTrace();
            }
            FileOutputStream fOut = null;
            try {
                    fOut = new FileOutputStream(f);
                    mBitmap.compress(Bitmap.CompressFormat.PNG, 100, fOut);
                    fOut.flush();
                    fOut.close();
            } catch (FileNotFoundException e) {
            	e.printStackTrace();
            } catch (IOException e) {
            	e.printStackTrace();
            }
    
        }
    	
        class CaptureListener implements OnClickListener{
    
    		@Override
    		public void onClick(View v) {
    			// TODO Auto-generated method stub
    			//new CapThread().start();
    			//Fimcgzsd.streamoff();
    			saveMyBitmap(bitmap);
    			//Fimcgzsd.streamon();
    			Toast.makeText(MainActivity.this, "Capture Successfully", Toast.LENGTH_LONG).show();
    		}
        	
        }
        
    	class CapThread extends Thread {
    
    		@Override
    		public void run() {
    			// TODO Auto-generated method stub
    			//super.run();
    			saveMyBitmap(bitmap);
    			Toast.makeText(MainActivity.this, "Capture Successfully", Toast.LENGTH_LONG).show();
    		}
    		
    	}
    	
    	@Override
    	protected void onStop() {
    		// TODO Auto-generated method stub
    		super.onStop();
    		Fimcgzsd.release();
    		finish();
    	}
    
    	@Override
    	protected void onPause() {
    		// TODO Auto-generated method stub
    		super.onPause();
    		Fimcgzsd.release();
    		finish();
    	}
    
    	@Override
    	protected void onDestroy() {
    		// TODO Auto-generated method stub
    		super.onDestroy();
    		Fimcgzsd.release();
    	}
    
    	@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);
    		finish();
    		return true;
    	}
    
    }

整体过程 其实很简单

首先open

这里usb camera设备为/dev/video3 为了修改方面所以我把这个参数放在应用层里传到HAL层 分辨率为640\*480

然后init

Fimcgzsd.init(width, height, numbuf);

传入宽，高 以及 缓冲帧的数目

然后开启视频流

Fimcgzsd.streamon();

开另外一个进程 循环获取数据 由于这里获取到的数据直接是jpeg格式的所以 我直接把他转成bmp然后用imageview直接显示 又省了不少事

贴上我的效果图

![Center][]

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