Android相机Camera基础知识

一、概述
本章节主要讲述的Android相机Camera的相关知识点，主要包含三个方面，Android启动系统相机生成缩略图、Android启动系统相机生成原图以及Android自定义相机等。

二、Android启动系统相机

核心代码：

package com.czhappy.camerademo.activity;import android.content.Intent;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.net.Uri;import android.os.Bundle;import android.os.Environment;import android.provider.MediaStore;import android.support.v7.app.AppCompatActivity;import android.view.View;import android.widget.ImageView;import com.czhappy.camerademo.R;import java.io.File;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.IOException;public class MainActivity extends AppCompatActivity {  private static int REQ_1 = 1;  private static int REQ_2 = 2;  private ImageView image_iv;  private String mFilePath;  @Override  protected void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_main);    image_iv = (ImageView) findViewById(R.id.image_iv);    mFilePath = Environment.getExternalStorageDirectory().getPath();    mFilePath = mFilePath +"/" + System.currentTimeMillis()+".jpg";  }  public void startCamera1(View view){    //隐式Intent调用    Intent it = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);    startActivityForResult(it, REQ_1);  }  public void startCamera2(View view){    //隐式Intent调用    Intent it = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);    Uri photoUri = Uri.fromFile(new File(mFilePath));    it.putExtra(MediaStore.EXTRA_OUTPUT, photoUri);    startActivityForResult(it, REQ_2);  }  public void customCamera(View view){    Intent it = new Intent(MainActivity.this, CustomCameraActivity.class);    startActivity(it);  }  /**   *   * @param requestCode   * @param resultCode   * @param data //缩略图   */  @Override  protected void onActivityResult(int requestCode, int resultCode, Intent data) {    super.onActivityResult(requestCode, resultCode, data);    if(resultCode == RESULT_OK){      if(requestCode == REQ_1){//缩略图        Bundle bundle = data.getExtras();        Bitmap bmp = (Bitmap) bundle.get("data");        image_iv.setImageBitmap(bmp);      }else if(requestCode == REQ_2){//原图        FileInputStream fis = null;        try {          fis = new FileInputStream(mFilePath);          Bitmap bitmap = BitmapFactory.decodeStream(fis);          image_iv.setImageBitmap(bitmap);        } catch (FileNotFoundException e) {          e.printStackTrace();        }finally {          try {            fis.close();          } catch (IOException e) {            e.printStackTrace();          }        }      }    }  }}

三、Android自定义相机

1.自定义相机步骤：

创建相机
创建SurfaceView
关联相机与SurfaceView
调整相机显示效果
自定义相机预览界面

2.核心代码：
自定义相机CustomCameraActivity.java

package com.czhappy.camerademo.activity;import android.content.Intent;import android.graphics.ImageFormat;import android.hardware.Camera;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.view.SurfaceHolder;import android.view.SurfaceView;import android.view.View;import com.czhappy.camerademo.R;import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;/** * Description: * User: chenzheng * Date: 2016/12/27 0027 * Time: 13:43 */public class CustomCameraActivity extends AppCompatActivity implements SurfaceHolder.Callback{  private SurfaceView mPreview;  private Camera mCamera;  private SurfaceHolder mHolder;  private Camera.PictureCallback mPictureCallback = new Camera.PictureCallback() {    @Override    public void onPictureTaken(byte[] data, Camera camera) {      File tempFile = new File("/sdcard/temp.png");      try {        FileOutputStream fos = new FileOutputStream(tempFile);        fos.write(data);        fos.close();        Intent it = new Intent(CustomCameraActivity.this, CaptureResultActivity.class);        it.putExtra("picPath", tempFile.getAbsolutePath());        startActivity(it);        finish();      } catch (FileNotFoundException e) {        e.printStackTrace();      } catch (IOException e) {        e.printStackTrace();      }    }  };  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_custom_camera);    mPreview = (SurfaceView) this.findViewById(R.id.preview);    mHolder = mPreview.getHolder();    mHolder.addCallback(this);    //点击自动对焦    mPreview.setOnClickListener(new View.OnClickListener() {      @Override      public void onClick(View v) {        mCamera.autoFocus(null);;      }    });  }  /**   * 拍照   * @param view   */  public void capture(View view){    Camera.Parameters parameters = mCamera.getParameters();    parameters.setPictureFormat(ImageFormat.JPEG);    parameters.setPictureSize(800,400);    parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);//自动对焦    mCamera.autoFocus(new Camera.AutoFocusCallback() {      @Override      public void onAutoFocus(boolean success, Camera camera) {        //对焦准确拍摄照片        if(success){          mCamera.takePicture(null, null, mPictureCallback);        }      }    });  }  /**   * 获取相机对象   * @return   */  private Camera getCamera(){    mCamera = Camera.open();    return mCamera;  }  /**   * 开始预览相机内容   */  private void setStartPreview(Camera camera, SurfaceHolder holder){    try {      camera.setPreviewDisplay(holder);      camera.setDisplayOrientation(90);//设置相机预览为竖屏90度      camera.startPreview();    } catch (IOException e) {      e.printStackTrace();    }  }  /**   * 释放相机资源   */  private void releaseCamera(){    if(mCamera!=null){      mCamera.setPreviewCallback(null);      mCamera.stopPreview();      mCamera.release();      mCamera = null;    }  }  @Override  protected void onResume() {    super.onResume();    if (mCamera==null){      mCamera = getCamera();      if(mHolder!=null){        setStartPreview(mCamera, mHolder);      }    }  }  @Override  protected void onPause() {    super.onPause();    releaseCamera();  }  @Override  public void surfaceCreated(SurfaceHolder holder) {    setStartPreview(mCamera, mHolder);  }  @Override  public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {    mCamera.stopPreview();    setStartPreview(mCamera, mHolder);  }  @Override  public void surfaceDestroyed(SurfaceHolder holder) {    releaseCamera();  }}

生成图片结果页面CaptureResultActivity.java

package com.czhappy.camerademo.activity;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Matrix;import android.os.Bundle;import android.support.v7.app.AppCompatActivity;import android.widget.ImageView;import com.czhappy.camerademo.R;import java.io.FileInputStream;import java.io.FileNotFoundException;/** * Description: * User: chenzheng * Date: 2016/12/30 0030 * Time: 13:27 */public class CaptureResultActivity extends AppCompatActivity {  private String picPath;  private ImageView result_iv;  @Override  public void onCreate(Bundle savedInstanceState) {    super.onCreate(savedInstanceState);    setContentView(R.layout.activity_capture_result);    picPath = getIntent().getStringExtra("picPath");    result_iv = (ImageView) findViewById(R.id.result_iv);    try {      FileInputStream fis = new FileInputStream(picPath);      Bitmap bitmap = BitmapFactory.decodeStream(fis);      Matrix matrix = new Matrix();      matrix.setRotate(90);//旋转90度矩阵      bitmap = Bitmap.createBitmap(bitmap, 0, 0, bitmap.getWidth(), bitmap.getHeight(), matrix, true);      result_iv.setImageBitmap(bitmap);    } catch (FileNotFoundException e) {      e.printStackTrace();    }  }}

四、项目源代码下载

http://xiazai.jb51.net/201701/yuanma/AndroidCamera(jb51.net).rar

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持脚本之家。

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