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。