Android开发之初识Camera图像采集

下面记录一个简单的相机的制作方法。

制作相机，首先需要添加照相的权限。添加方法是在AndroidManifest.xml文件中添加

<uses-permission android:name=” android.permission.CAMERA”>

注意这里是uses不是user否则会报错链接无法连接camera的错误

其次：修改布局文件：如下代码所示。

<?xml version="1.0" encoding="utf-8"?> 
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:orientation="vertical" 
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 
    > 
    <SurfaceView 
    android:id = "@+id/mySurfaceView" 
    android:layout_width="320px" 
    android:layout_height="240px"> 
    </SurfaceView> 
    <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" 
    android:layout_width="fill_parent" 
    android:layout_height="wrap_content" 
    > 
<Button 
android:id="@+id/myButton"  
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="打开"/> 
<Button 
android:id="@+id/myButton2"  
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:text="关闭"/> 
</LinearLayout> 
</LinearLayout> 

package tcamera.n.com.tcamera;
import android.app.Activity;
import android.hardware.Camera;
import android.hardware.Camera.ErrorCallback;
import java.io.IOException;
import android.os.Bundle;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceHolder.Callback;
import android.view.SurfaceView;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;

public class MainActivity extends Activity implements Callback {

    Camera myCamera;
    SurfaceView mySurfaceView;
    SurfaceHolder mySurfaceHolder;
    Button myButton1;
    Button myButton2;
    boolean isPreview = false;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.tcam);

        mySurfaceView = (SurfaceView) findViewById(R.id.mySurfaceView);
        myButton1 = (Button) findViewById(R.id.myButton);
        myButton2 = (Button) findViewById(R.id.myButton2);

        mySurfaceHolder = mySurfaceView.getHolder();
        mySurfaceHolder.addCallback(this);
        mySurfaceHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
        myButton1.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {
                initCamera();
            }
        });
        myButton2.setOnClickListener(new Button.OnClickListener() {

            @Override
            public void onClick(View v) {
                if (myCamera != null & isPreview) {
                    myCamera.stopPreview();
                    myCamera.release();
                    myCamera = null;
                    isPreview = false;
                }
            }

        });
    }

    public void initCamera() {

        if (!isPreview) {
            myCamera = Camera.open(0);
        }
        if (myCamera != null & !isPreview) {
            try {
                myCamera.setPreviewDisplay(mySurfaceHolder);
                myCamera.startPreview();
            } catch (IOException e) {
                e.printStackTrace();
            }
            isPreview = true;
        }
    }

    @Override
    public void surfaceChanged(SurfaceHolder holder, int format, int width,
                               int height) {

    }

    @Override
    public void surfaceCreated(SurfaceHolder holder) {

    }

    @Override
    public void surfaceDestroyed(SurfaceHolder holder) {

    }
}

如果在模拟器中运行，可以得到如图所示的情形。如果在真机上运行，则会打开摄像头，将实际的影响显现出来。关闭时，则定在关闭时的画面。这样基本可以完成了图像的采集。如果程序中对相机有要求的话，可以采用这种方式进行