本文导航
- Camera的源码分析
- 获取Camera的缩略图
- 获取Camera的完整图片
- 获取Gallery的图片
源码部分分析
通过源码可以发现,输出的图片有2个分支
如果你没有指定Intent里面的Extra参数,它就返回一个序列化(putExtra(“data”, bitmap))的Bitmap,从理论上来说,这样的代码写的很烂,属于Magic Number。
如果你指定了Intent里面的Extra参数MediaStore.EXTRA_OUTPUT,拍照后它就直接把bitmap写到了Uri里面了,返回是空
获得拍照的预览图
使用范围:获得很小的预览图,用于设置头像等地方。
返回示例:bitmap = data.getExtras().getParcelable(“data”);
public final static int REQUEST_IMAGE_CAPTURE = 1;
//start
Intent intent = new Intent(android.provider.MediaStore.ACTION_IMAGE_CAPTURE);
startActivityForResult(intent, REQUEST_IMAGE_CAPTURE);
//receive
@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode != RESULT_OK) {
Log.d(TAG, "canceled or other exception!");
return;
}
if (requestCode == REQUEST_IMAGE_CAPTURE) {
Log.d(TAG, "REQUEST_IMAGE_CAPTURE");
Bitmap bitmap;
try {
//"data"这个居然没用常量定义,也是醉了,我们可以发现它直接把bitmap序列化到intent里面了。
bitmap = data.getExtras().getParcelable("data");
//TODO:do something with bitmap, Do NOT forget call Bitmap.recycler();
mCameraImageview.setImageBitmap(bitmap);
} catch (ClassCastException e){
//do something with exceptions
e.printStackTrace();
}
}
}
获得原始的拍照文件
使用范围:用于处理大的图片,比如使用滤镜,上传原始图像等操作,注意Uri不要用data私有目录,否则相机是写不进去的。
返回示例:
outputFileUri = file:///storage/sdcard0/JPEG_20150226_221320_-328629202.jpg
使用方法:
public final static int REQUEST_IMAGE_CAPTURE = 1;
Uri outputFileUri;
//start
@OnClick(R.id.itemSelectCamera) void itemSelectCamera() {
File file = FileUtils.createImageFile();
outputFileUri = Uri.fromFile(file);
Intent captureIntent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
captureIntent.putExtra(MediaStore.EXTRA_OUTPUT, outputFileUri);
startActivityForResult(captureIntent, REQUEST_IMAGE_CAPTURE);
}
//receive
@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode != RESULT_OK) {
Log.d(TAG, "canceled or other exception!");
return;
}
if (requestCode == REQUEST_IMAGE_CAPTURE) {
Log.d(TAG, "REQUEST_IMAGE_CAPTURE");
//TODO:Use the Uri
Intent intent = new Intent(this, ImageFilterActivity.class);
intent.setData(outputFileUri);
startActivity(intent);
}
}
关于文件如何创建,目前我找到的就是这个最稳定了,写到SD卡根目录(每个手机位置都不一样,坑太多了),再说一遍,data目录(Context.getXXDir())是私有目录,其它程序(比如Camera)是写不进去的
public class FileUtils {
public static File createImageFile() {
// Create an image file name
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss").format(new Date());
String imageFileName = "JPEG_" + timeStamp + "_";
try {
File image = File.createTempFile(imageFileName, /* prefix */
".jpg", /* suffix */
Environment.getExternalStorageDirectory() /* directory */);
return image;
} catch (IOException e) {
//do noting
return null;
}
}
}
获取Gallery里面的图片
用途:获取MINETYPE为”image/*”的图片
返回示例 :
content://com.android.providers.media.documents/document/image%3A445
使用方法:
public final static int REQUEST_IMAGE_SELECT = 2;
@OnClick(R.id.itemSelectGallery) void itemSwitches() {
Intent intent = new Intent(Intent.ACTION_PICK);
intent.setType("image/*");
intent.setAction(Intent.ACTION_GET_CONTENT);
startActivityForResult(intent, REQUEST_IMAGE_SELECT);
}
@Override protected void onActivityResult(int requestCode, int resultCode, Intent data) {
super.onActivityResult(requestCode, resultCode, data);
if (resultCode != RESULT_OK) {
Log.d(TAG, "canceled or other exception!");
return;
}
if (requestCode == REQUEST_IMAGE_SELECT) {
Log.d(TAG, "REQUEST_IMAGE_SELECT");
//TODO:Use Uri
Intent intent = new Intent(this, ImageFilterActivity.class);
intent.setData(data.getData());
startActivity(intent);
}
}
总结
这篇文章绝对比stackoverflow上的许多回答都更加完整,我花了很多时间查了很多的方案,最后定下来这三种方法是最好的。
摘录来自:简书作者