Android呼叫系統照相機返回intent為空原因分析
1.在呼叫android系統相簿時,使用的是如下方式:
Intent intent = new Intent(Intent.ACTION_GET_CONTENT);
intent.addCategory(Intent.CATEGORY_OPENABLE);
intent.setType("image/");
startActivityForResult(intent,1);
在onActivityResult 中通過data獲取資料可以正常獲取:
if (requestCode ==
1)
{
Uri uri = null;
if (null != data || resultCode == RESULT_OK)
{
uri = data.getData();
String filePath = getRealPathFromUri(this,uri);
Log.d("filepath",filePath);
if (null == filePath || filePath.equals(""))
{
return;
}
//得到了檔案路徑,可以執行相應壓縮上傳操作,
}
}
super.onActivityResult(requestCode, resultCode, data);
public static String getRealPathFromUri(Context context, Uri contentUri) {
Cursor cursor = null;
try {
String[] proj = { MediaStore.Images.Media.DATA };
cursor = context.getContentResolver().query(contentUri, proj, null, null, null);
if (null == cursor )
{
return "";
}
if (cursor.moveToFirst())
{
return cursor.getString(0);
}
}catch (Exception e)
{
Log.w("resolvepic",e.getMessage());
}
finally {
if (cursor != null) {
cursor.close();
}
}
return "";
}
2.回到正題,如何呼叫系統照相機呢?如下:
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
// 指定存放拍攝照片的位置
File filePath = createImageFile();
intent.putExtra(MediaStore.EXTRA_OUTPUT, Uri.fromFile(filePath));
startActivityForResult(intent, 2);
------------------------------------------------------我是分隔線------------------------------------------------------private File createImageFile() throws IOException {
SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd_HHmmss");
String timeStamp = format.format(System.currentTimeMillis());
String imageFileName = "hxjysj_" + timeStamp + ".jpg";
File image = new File(PictureUtil.getAlbumDir(this), imageFileName);
mCurrentPhotoPath = image.getAbsolutePath();
return image;
在onActivityResult中:
protected void onActivityResult(int requestCode, int resultCode, Intent intent)
其中intent得到的結果總是為null???
檢視相關資料發現,如果指定intent.putExtra(MediaStore.EXTRA_OUT,uri);
則intent拿到的是null. 如果沒有指定uri,則intent就會有資料的返回.
照相機會有自己的預設的儲存路徑,如果想得到圖片的路徑,則可以通過
Bitmap bitmap = (Bitmap)intent.getParcelableExtra("data");得到bitmap再進行圖片的壓縮展示等相關的操作.3.附Camera.java部分原始碼:
private Bitmap createCaptureBitmap(byte[] data) {
// This is really stupid...we just want to read the orientation in
// the jpeg header.
String filepath = ImageManager.getTempJpegPath();
int degree = 0;
if (saveDataToFile(filepath, data)) {
degree = ImageManager.getExifOrientation(filepath);
new File(filepath).delete();
}
//縮放的點陣圖bitmap只有50k,如果還想得到高質量的圖片還是指定圖片路徑吧.// Limit to 50k pixels so we can return it in the intent.
Bitmap bitmap = Util.makeBitmap(data, 50 * 1024);
bitmap = Util.rotate(bitmap, degree);
return bitmap;
}
private void doAttach() {
if (mPausing) {
return;
}
byte[] data = mImageCapture.getLastCaptureData();
if (mCropValue == null) {
// First handle the no crop case -- just return the value. If the
// caller specifies a "save uri" then write the data to it's
// stream. Otherwise, pass back a scaled down version of the bitmap
// directly in the extras.//如果指定uri就會儲存到指定的uri中,否則,通過縮放點陣圖的縮放版本
if (mSaveUri != null) { //這裡說明的就是設定了指定儲存的uri地址
OutputStream outputStream = null;
try {
outputStream = mContentResolver.openOutputStream(mSaveUri);
outputStream.write(data);
outputStream.close();
//設定了成功的返回狀態.
setResult(RESULT_OK);
finish();
} catch (IOException ex) {
// ignore exception
} finally {
Util.closeSilently(outputStream);
}
} else {
Bitmap bitmap = createCaptureBitmap(data);
setResult(RESULT_OK,
new Intent("inline-data").putExtra("data", bitmap));//如果沒有設定指定的儲存地址.intent就會有資料返回.
//在onActivityResult中可以通過如下方式得到一個bitmap物件再進行操作:
//Bitmap bitmap = (Bitmap)intent.getParcelableExtra("data");finish();
}
} else {
// Save the image to a temp file and invoke the cropper
Uri tempUri = null;
FileOutputStream tempStream = null;
try {
File path = getFileStreamPath(sTempCropFilename);
path.delete();
tempStream = openFileOutput(sTempCropFilename, 0);
tempStream.write(data);
tempStream.close();
tempUri = Uri.fromFile(path);
} catch (FileNotFoundException ex) {
setResult(Activity.RESULT_CANCELED);
finish();
return;
} catch (IOException ex) {
setResult(Activity.RESULT_CANCELED);
finish();
return;
} finally {
Util.closeSilently(tempStream);
}
Bundle newExtras = new Bundle();
if (mCropValue.equals("circle")) {
newExtras.putString("circleCrop", "true");
}
if (mSaveUri != null) {
newExtras.putParcelable(MediaStore.EXTRA_OUTPUT, mSaveUri);
} else {
newExtras.putBoolean("return-data", true);
}
Intent cropIntent = new Intent("com.android.camera.action.CROP");
cropIntent.setData(tempUri);
cropIntent.putExtras(newExtras);
startActivityForResult(cropIntent, CROP_MSG);
}
}