这篇博客为大家介绍Android自定义相机，并且实现倒计时拍照功能
首先自定义拍照会用到SurfaceView控件显示照片的预览区域，以下是布局文件：
两个TextView是用来显示提示信息和倒计时的秒数的
<RelativeLayout 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:background="#266194"
android:orientation="vertical"
tools:context=".TestActivity" > <SurfaceView
android:id="@+id/surfaceView"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_centerInParent="true" /> <LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_centerInParent="true"
android:orientation="vertical" > <TextView
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="请调整位置到此区域"
android:textColor="#ff0000"
android:textSize="32sp" /> <TextView
android:id="@+id/tv_time"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:paddingTop="10dp"
android:gravity="center_horizontal"
android:textColor="#266194"
android:textSize="32sp" />
</LinearLayout> </RelativeLayout>
接下来是mainActivity中的具体实现以及详细注释：
package com.dhsr.pujiejia.ui; import java.io.File;
import java.io.FileOutputStream;
import java.text.SimpleDateFormat;
import java.util.Date; import android.annotation.SuppressLint;
import android.app.Activity;
import android.content.Context;
import android.content.Intent;
import android.content.res.Configuration;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.PixelFormat;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.os.Bundle;
import android.os.Environment;
import android.os.Handler;
import android.view.SurfaceHolder;
import android.view.SurfaceView;
import android.view.Window;
import android.view.WindowManager;
import android.widget.TextView; import com.example.pujiejiaapp.R; @SuppressLint({ "NewApi", "SdCardPath" })
public class CameraActivity extends Activity implements Runnable {
// 预览图片范围
private SurfaceView surfaceView;
private TextView tv_time;
// 倒计时拍摄
private int cameratime = 4;
private Camera camera;
private boolean preview = false;
// 文件名字
private String filename;
// 文件名字的带的时间戳
private String timeString;
// 格式化时间
private SimpleDateFormat dateFormat;
// 日期对象
private Date date;
// 控制线程
boolean stopThread = false;
private File file;
String photo; private Handler mHandler = new Handler() {
public void handleMessage(android.os.Message msg) {
int what = msg.what;
switch (what) {
case 222:
tv_time.setText("" + cameratime);
if ("0".equals(tv_time.getText().toString())) {
tv_time.setText("拍摄成功！");
takePhoto();
}
break; }
};
}; @Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_test);
CameraActivity.this.setFinishOnTouchOutside(false);
// 初始化数据
findView();
surfaceView.getHolder().addCallback(new SufaceListener());
/* 下面设置Surface不维护自己的缓冲区，而是等待屏幕的渲染引擎将内容推送到用户面前 */
surfaceView.getHolder()
.setType(SurfaceHolder.SURFACE_TYPE_PUSH_BUFFERS);
surfaceView.getHolder().setFixedSize(200, 200); // 设置分辨率
} @Override
protected void onStart() {
// TODO Auto-generated method stub
super.onStart();
// 开启线程
new Thread(this).start();
} private final class SufaceListener implements SurfaceHolder.Callback {
/**
* surface改变
*/
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width,
int height) {
} /**
* surface创建
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
try {
for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
CameraInfo info = new CameraInfo();
Camera.getCameraInfo(i, info);
// 调用系统的前置摄像头
if (info.facing == CameraInfo.CAMERA_FACING_FRONT) {
camera = Camera.open(i);
}
}
Camera.Parameters parameters = camera.getParameters();
/* 每秒从摄像头捕获5帧画面， */
parameters.setPreviewFrameRate(5);
/* 设置照片的输出格式:jpg */
parameters.setPictureFormat(PixelFormat.JPEG);
/* 照片质量 */
parameters.set("jpeg-quality", 85);
WindowManager wm = (WindowManager) getSystemService(Context.WINDOW_SERVICE);
camera.setParameters(parameters);
camera.setPreviewDisplay(surfaceView.getHolder());// 通过SurfaceView显示取景画面
camera.startPreview();
preview = true;
} catch (Exception e) { }
} /**
* surface销毁
*/
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
if (camera != null) {
if (preview)
camera.stopPreview();
camera.release();
camera = null;
}
}
} /**
* 拍摄照片
*/
private void takePhoto() {
// 执行拍照效果
camera.takePicture(null, null, new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
try {
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,
data.length);
timeString = formatDate();
//保存到data/data目录自定义文件夹下
filename = "/data/data/com.example.pujiejiaapp/images/"
+ timeString + ".jpg";
File file = new File(filename);
boolean createNewFile = file.createNewFile()
System.out.println("创建文件夹成功没有" + createNewFile);
System.out.println(file);
FileOutputStream outStream = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 60, outStream);
outStream.flush();
outStream.close();
// 重新浏览
camera.stopPreview();
camera.startPreview();
preview = true;
} catch (Exception e) {
e.printStackTrace();
} finally {
}
}
});
} @Override
public void run() {
while (!stopThread) {
try {
//按秒数倒计时
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
cameratime--;
mHandler.sendEmptyMessage(222);
if (cameratime <= 0) {
break;
}
}
} // 初始化数据
private void findView() {
surfaceView = (SurfaceView) this.findViewById(R.id.surfaceView);
tv_time = (TextView) findViewById(R.id.tv_time);
} // 格式化系统的时间
public String formatDate() {
date = new Date(System.currentTimeMillis());
// 日期格式
dateFormat = new SimpleDateFormat("'IMG'_yyyyMMddHHmmss");
return dateFormat.format(date);
} @Override
protected void onDestroy() {
// TODO Auto-generated method stub
// 线程已关闭
super.onDestroy();
stopThread = true;
} }
核心代码详解：
1.创建SurfaceView时，surfaceCreated()方法中
for (int i = 0; i < Camera.getNumberOfCameras(); i++) {
CameraInfo info = new CameraInfo();
Camera.getCameraInfo(i, info);
// 调用系统的前置摄像头
if (info.facing == CameraInfo.CAMERA_FACING_FRONT) {
camera = Camera.open(i);
}
}
此部分代码为打开相机时默认打开前置摄像头CameraInfo.CAMERA_FACING_BACK为默认打开后置摄像头，CameraInfo.CAMERA_FACING_FRONT前置摄像头
2.照片拍摄takePhoto()方法中：
Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0,
data.length);
timeString = formatDate();
filename = "/data/data/com.example.pujiejiaapp/images/"
+ timeString + ".jpg";
photo = timeString + ".jpg";
File file = new File(filename);
boolean createNewFile = file.createNewFile();
FileOutputStream outStream = new FileOutputStream(file);
bitmap.compress(Bitmap.CompressFormat.JPEG, 60, outStream);
此部分代码为将拍摄到的图片保存为以bitmap格式保存在指定的目录下
3.开子线程用于倒计时拍摄
public void run() {
while (!stopThread) {
try {
Thread.sleep(1000);
} catch (InterruptedException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
cameratime--;
mHandler.sendEmptyMessage(222);
if (cameratime <= 0) {
break;
}
}
}
希望大家理解核心代码的详细注释，欢迎提供意见，希望能给大家带来帮助，谢谢！