很多开发者都想在程序用来调用摄像头，并对拍出的照片进行处理。首先先对程序的进行一下预览
首先先对主页面进行设计，这里很简单，只是加了个按钮和一张图片
[html] <?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" >
<Button
android:id="@+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/camera" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_launcher" />
</LinearLayout>
<?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" >
<Button
android:id="@+id/button1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:text="@string/camera" />
<ImageView
android:id="@+id/imageView1"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:src="@drawable/ic_launcher" />
</LinearLayout>
接下来就是对按钮事件进行处理，按下按钮的时候会调用本机摄像头
[java] //图片存入地址www.2cto.com
imageFilePath = Environment.getExternalStorageDirectory()
.getAbsolutePath() + "/mypicture.jpg";
File imageFile = new File(imageFilePath);
Uri imageFileUri = Uri.fromFile(imageFile);
Intent i = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
i.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, imageFileUri);
startActivityForResult(i, CAMERA_RESULT);
//图片存入地址
imageFilePath = Environment.getExternalStorageDirectory()
.getAbsolutePath() + "/mypicture.jpg";
File imageFile = new File(imageFilePath);
Uri imageFileUri = Uri.fromFile(imageFile);
Intent i = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
i.putExtra(android.provider.MediaStore.EXTRA_OUTPUT, imageFileUri);
startActivityForResult(i, CAMERA_RESULT);
Intent直接调用了本机的拍照程序，并把拍的图片存在内存卡里，接下来就是要在我们自己的程序里显示拍的照片了
这里我们直接用了Activity里的onActivityResult这个方法，这个方法是对Activity返回结果的处理
[java] @Override
protected void onActivityResult(int requestCode, int resultCode,
Intent intent) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, intent);
//如果拍照成功
if (resultCode == RESULT_OK) {
// Bundle extras = intent.getExtras();
// Bitmap bmp = (Bitmap)extras.get("data");
imv = (ImageView) findViewById(R.id.imageView1);
//取得屏幕的显示大小
Display currentDisplay = getWindowManager().getDefaultDisplay();
int dw = currentDisplay.getWidth();
int dh = currentDisplay.getHeight();
//对拍出的照片进行缩放
BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
bmpFactoryOptions.inJustDecodeBounds = true;
Bitmap bmp = BitmapFactory.decodeFile(imageFilePath,
bmpFactoryOptions);
int heightRatio = (int) Math.ceil(bmpFactoryOptions.outHeight
/ (float) dh);
int widthRatio = (int) Math.ceil(bmpFactoryOptions.outWidth
/ (float) dw);
if (heightRatio > 1 && widthRatio > 1) {
if (heightRatio > widthRatio) {
bmpFactoryOptions.inSampleSize = heightRatio;
} else {
bmpFactoryOptions.inSampleSize = widthRatio;
}
}
bmpFactoryOptions.inJustDecodeBounds = false;
bmp = BitmapFactory.decodeFile(imageFilePath, bmpFactoryOptions);
imv.setImageBitmap(bmp);
}
}
@Override
protected void onActivityResult(int requestCode, int resultCode,
Intent intent) {
// TODO Auto-generated method stub
super.onActivityResult(requestCode, resultCode, intent);
//如果拍照成功
if (resultCode == RESULT_OK) {
// Bundle extras = intent.getExtras();
// Bitmap bmp = (Bitmap)extras.get("data");
imv = (ImageView) findViewById(R.id.imageView1);
//取得屏幕的显示大小
Display currentDisplay = getWindowManager().getDefaultDisplay();
int dw = currentDisplay.getWidth();
int dh = currentDisplay.getHeight();
//对拍出的照片进行缩放
BitmapFactory.Options bmpFactoryOptions = new BitmapFactory.Options();
bmpFactoryOptions.inJustDecodeBounds = true;
Bitmap bmp = BitmapFactory.decodeFile(imageFilePath,
bmpFactoryOptions);
int heightRatio = (int) Math.ceil(bmpFactoryOptions.outHeight
/ (float) dh);
int widthRatio = (int) Math.ceil(bmpFactoryOptions.outWidth
/ (float) dw);
if (heightRatio > 1 && widthRatio > 1) {
if (heightRatio > widthRatio) {
bmpFactoryOptions.inSampleSize = heightRatio;
} else {
bmpFactoryOptions.inSampleSize = widthRatio;
}
}
bmpFactoryOptions.inJustDecodeBounds = false;
bmp = BitmapFactory.decodeFile(imageFilePath, bmpFactoryOptions);
imv.setImageBitmap(bmp);
}
}
这里我们就完成了对本机摄像头的调用，其实在这里主要要学习的是startActivityForResult和onActivityResult这两个方法，一个是调用Activity并将结果返回给调用的Activity，一个就是处理返回的数据了，好了，如果哪位想要程序的话，可以直接留邮件地址。
摘自 kangkangz4的专栏
