照相机

通过隐式意图来打开照相机

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    tools:context=".MainActivity" >

    <Button
        android:onClick="click"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="拍照" />

    <ImageView 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/iv"
        />
</LinearLayout>

package com.itheima.camera;

import java.io.File;

import android.app.Activity;
import android.content.Intent;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.provider.MediaStore;
import android.view.View;
import android.widget.ImageView;

public class MainActivity extends Activity {
	private ImageView iv;
	private File file ;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		iv = (ImageView) findViewById(R.id.iv);
	}

	//打开的是前置摄像头
	public void click(View view) {
		Intent intent = new Intent();
		// 指定拍照的意图。
//		MediaStore.ACTION_VIDEO_CAPTURE是录像的意图
		intent.setAction(MediaStore.ACTION_IMAGE_CAPTURE);
		file =  new File(Environment.getExternalStorageDirectory(),System.currentTimeMillis()+".jpg");
		intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(file)); // 指定保存文件的路径
		startActivityForResult(intent, 100);												
	}
	@Override
	protected void onActivityResult(int requestCode, int resultCode, Intent data) {
		if(requestCode==100){
			iv.setImageURI(Uri.fromFile(file));
		}
		super.onActivityResult(requestCode, resultCode, data);
	}
}

偷拍神奇

    把预览框缩小成一个点拍照

通过Camera启动拍照资源

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:orientation="vertical"
    android:layout_height="match_parent"
    tools:context=".MainActivity" >

    <Button
        android:onClick="click"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:text="拍照" />

     <FrameLayout
         android:id="@+id/camera_preview"
         android:layout_width="100dip"
         android:layout_height="100dip"
         />

    <ImageView 
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:id="@+id/iv"
        />
</LinearLayout>

package com.itheima.camera2;

import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.hardware.Camera;
import android.hardware.Camera.AutoFocusCallback;
import android.hardware.Camera.PictureCallback;
import android.hardware.Camera.ShutterCallback;
import android.os.Bundle;
import android.os.Environment;
import android.os.SystemClock;
import android.app.Activity;
import android.view.Menu;
import android.view.View;
import android.widget.FrameLayout;
import android.widget.ImageView;
import android.widget.Toast;

public class MainActivity extends Activity {
	private ImageView iv;
	private Camera mCamera;
	private CameraPreview mPreview;

	@Override
	protected void onCreate(Bundle savedInstanceState) {
		super.onCreate(savedInstanceState);
		setContentView(R.layout.activity_main);
		iv = (ImageView) findViewById(R.id.iv);
		 // Create an instance of Camera
        mCamera = getCameraInstance();
        // Create our Preview view and set it as the content of our activity.
        //获取预览界面
        mPreview = new CameraPreview(this, mCamera);
        FrameLayout preview = (FrameLayout) findViewById(R.id.camera_preview);
        //把预览界面加到帧布局
        preview.addView(mPreview);
	}
	public void click(View view){
		//拍照前先自动对焦一下
		mCamera.autoFocus(new AutoFocusCallback() {
			//对焦完毕后拍照
			@Override
			public void onAutoFocus(boolean success, Camera camera) {
				//第一参数为null  不关心快门
				//数码相机拍出的默认照片是bitmap，没有经过压缩，体积过大，觉得体积过大了就可以null不去关心回调
				mCamera.takePicture(null, null, new PictureCallback() {
					@Override
					public void onPictureTaken(byte[] data, Camera camera) {
						try {
							File file = new File(Environment.getExternalStorageDirectory(),SystemClock.uptimeMillis()+".jpg");
							FileOutputStream fos = new FileOutputStream(file);
							fos.write(data);
							fos.close();
							Toast.makeText(getApplicationContext(), "成功", 0).show();
							//拍完照片的时候，照片还是被占用的，如果还想再拍照，一定要先释放掉照相机的资源
							//重新开启预览
							mCamera.startPreview();
						} catch (Exception e) {
							e.printStackTrace();
						}
					}
				});
			}
		});
		
        
	}
	/** 获取一个照相机实例 */
	public static Camera getCameraInstance(){
		//导入的是hardware包
	    Camera c = null;
	    try {
	    	//打开照相机   open参数为1就是前置摄像头，空或者2就是后置摄像头
	        c = Camera.open(); // attempt to get a Camera instance
	    }
	    catch (Exception e){
	        // Camera is not available (in use or does not exist)
	    }
	    return c; // returns null if camera is unavailable
	}
	@Override
	protected void onDestroy() {
		//如果退出界面  要先停止照相机
		mCamera.stopPreview();
		//停止照相机之后就释放掉照相机资源
		mCamera.release();
		mCamera = null;
		super.onDestroy();
	}
}

package com.itheima.camera2;

import java.io.IOException;

import android.content.Context;
import android.hardware.Camera;
import android.util.Log;
import android.view.SurfaceHolder;
import android.view.SurfaceView;

/** A basic Camera preview class */
public class CameraPreview extends SurfaceView implements SurfaceHolder.Callback {
    private static final String TAG = "CameraPreview";
	private SurfaceHolder mHolder;
    private Camera mCamera;

    public CameraPreview(Context context, Camera camera) {
        super(context);
        mCamera = camera;

        // Install a SurfaceHolder.Callback so we get notified when the
        // underlying surface is created and destroyed.
        mHolder = getHolder();
        mHolder.addCallback(this);
        // deprecated setting, but required on Android versions prior to 3.0
        mHolder.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
    }

    public void surfaceCreated(SurfaceHolder holder) {
        // The Surface has been created, now tell the camera where to draw the preview.
        try {
            mCamera.setPreviewDisplay(holder);
            mCamera.startPreview();
        } catch (IOException e) {
            Log.d(TAG, "Error setting camera preview: " + e.getMessage());
        }
    }

    public void surfaceDestroyed(SurfaceHolder holder) {
        // empty. Take care of releasing the Camera preview in your activity.
    }

    //屏幕宽高发生变化的时候触发
    public void surfaceChanged(SurfaceHolder holder, int format, int w, int h) {
        // If your preview can change or rotate, take care of those events here.
        // Make sure to stop the preview before resizing or reformatting it.

        if (mHolder.getSurface() == null){
          // preview surface does not exist
          return;
        }

        // stop preview before making changes
        try {
            mCamera.stopPreview();
        } catch (Exception e){
          // ignore: tried to stop a non-existent preview
        }

        // set preview size and make any resize, rotate or
        // reformatting changes here

        // start preview with new settings
        try {
            mCamera.setPreviewDisplay(mHolder);
            mCamera.startPreview();

        } catch (Exception e){
            Log.d(TAG, "Error starting camera preview: " + e.getMessage());
        }
    }
}