1、打开相机
a.预览拍摄图片，需用到SurfaceView，并且实现其回调函数implements SurfaceHolder.Callback；
activity_camera.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical" >
<SurfaceView
android:id="@+id/sv"
android:layout_width="match_parent"
android:layout_height="0dp"
android:layout_weight="1" />
<Button
android:id="@+id/btn_camera"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="拍照" />
</LinearLayout>
2、获取相机并开启预览
/**
* 获取系统相机
*
* @return
*/
private Camera getcCamera() {
Camera camera = null;
try {
camera = Camera.open();
} catch (Exception e) {
camera = null;
}
return camera;
}
/**
* 显示相机预览图片
*
* @return
*/
private void showCameraView(Camera camera,SurfaceHolder holder)
{
try {
camera.setPreviewDisplay(holder);
camera.setDisplayOrientation(90);
camera.startPreview();
}catch (Exception e){
e.printStackTrace();
};
}
/**
** 实现界面回调处理
*/
@Override
public void surfaceCreated(SurfaceHolder holder) {
showCameraView(mCamera, holder);
}
@Override
public void surfaceChanged(SurfaceHolder holder, int format, int width, int height) {
mCamera.stopPreview();
showCameraView(mCamera, holder);
}
@Override
public void surfaceDestroyed(SurfaceHolder holder) {
clearCamera();
}
}
3、相机主页面处理
public class CameraActivity extends AppCompatActivity implements SurfaceHolder.Callback{
private SurfaceView sv;
private Camera mCamera;
private SurfaceHolder holder;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_camera);
sv = (SurfaceView)findViewById(R.id.sv);
holder = sv.getHolder();
holder.addCallback(this);
findViewById(R.id.btn_camera).setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// 获取当前相机参数
Camera.Parameters parameters = mCamera.getParameters();
// 设置相片格式
parameters.setPictureFormat(ImageFormat.JPEG);
// 设置预览大小
parameters.setPreviewSize(800, 480);
// 设置对焦方式，这里设置自动对焦
parameters.setFocusMode(Camera.Parameters.FOCUS_MODE_AUTO);
mCamera.autoFocus(new Camera.AutoFocusCallback() {
@Override
public void onAutoFocus(boolean success, Camera camera) {
// 判断是否对焦成功
if (success) {
// 拍照 第三个参数为拍照回调
mCamera.takePicture(null, null, new Camera.PictureCallback() {
@Override
public void onPictureTaken(byte[] data, Camera camera) {
// data为完整数据
File file = new File("/sdcard/photo.png");
// 使用流进行读写
try {
FileOutputStream fos = new FileOutputStream(file);
try {
fos.write(data);
// 关闭流
fos.close();
// 查看图片
Intent intent = new Intent();
// 传递路径
intent.putExtra("path", file.getAbsolutePath());
setResult(0,intent);
finish();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
} catch (FileNotFoundException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
});
}
}
});
}
});
}
@Override
protected void onResume() {
super.onResume();
if (mCamera == null) {
mCamera = getCamera();
if (holder != null) {
showCameraView(mCamera, holder);
}
}
}
@Override
protected void onPause() {
// TODO Auto-generated method stub
super.onPause();
// activity暂停时我们释放相机内存
clearCamera();
}
@Override
protected void onDestroy() {
super.onDestroy();
}
/**
* 释放相机的内存
*/
private void clearCamera() {
// 释放hold资源
if (mCamera != null) {
// 停止预览
mCamera.stopPreview();
mCamera.setPreviewCallback(null);
// 释放相机资源
mCamera.release();
mCamera = null;
}
}
4、启动activity（设置拍照完图片路径返回显示图片处理，一定要对图片进行采样率操作（很可能拍照的图片太多而无法显示，又不报任何异常））
public class MainActivity extends AppCompatActivity {
private ImageView cameraIv;
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
if(resultCode == 0 && requestCode == 100)
{
String path = data.getStringExtra("path");
BitmapFactory.Options options = new BitmapFactory.Options();
options.inJustDecodeBounds = true;
BitmapFactory.decodeFile(path, options);
ImageSize imageSize = getImageViewSize(cameraIv);
options.inSampleSize = caculateInSampleSize(options,
imageSize.width, imageSize.height);
// 使用获得到的InSampleSize再次解析图片
options.inJustDecodeBounds = false;
Bitmap bitmap = BitmapFactory.decodeFile(path, options);
cameraIv.setImageBitmap(bitmap);
}
super.onActivityResult(requestCode, resultCode, data);
}
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button openButton = (Button) findViewById(R.id.button);
cameraIv = (ImageView) findViewById(R.id.imageView);
openButton.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
Intent intent = new Intent(MainActivity.this,CameraActivity.class);
startActivityForResult(intent,100);
}
});
}
/* 根据需求的宽和高以及图片实际的宽和高计算SampleSize
*
* @param options
* @param width
* @param height
* @return
*/
public static int caculateInSampleSize(BitmapFactory.Options options, int reqWidth,
int reqHeight)
{
int width = options.outWidth;
int height = options.outHeight;
int inSampleSize = 1;
if (width > reqWidth || height > reqHeight)
{
int widthRadio = Math.round(width * 1.0f / reqWidth);
int heightRadio = Math.round(height * 1.0f / reqHeight);
inSampleSize = Math.max(widthRadio, heightRadio);
}
return inSampleSize;
}
public static ImageSize getImageViewSize(ImageView imageView)
{
ImageSize imageSize = new ImageSize();
DisplayMetrics displayMetrics = imageView.getContext().getResources()
.getDisplayMetrics();
LinearLayout.LayoutParams lp = (LinearLayout.LayoutParams)imageView.getLayoutParams();
int width = imageView.getWidth();// 获取imageview的实际宽度
if (width <= 0)
{
width = lp.width;// 获取imageview在layout中声明的宽度
}
if (width <= 0)
{
width = displayMetrics.widthPixels;
}
int height = imageView.getHeight();// 获取imageview的实际高度
if (height <= 0)
{
height = lp.height;// 获取imageview在layout中声明的宽度
}
if (height <= 0)
{
height = displayMetrics.heightPixels;
}
imageSize.width = width;
imageSize.height = height;
return imageSize;
}
public static class ImageSize
{
int width;
int height;
}
}
