I am new to Android development. I created my first app which is a camera with the ability to capture an image, query the user for a Car ID related to the image, preview the captured image, and upload that image to the server.
I am interested in sending a random image from the directory of captured images to the server without knowing exactly which image from the directory was sent out. I do NOT want the user to have the capability of selecting an image(s) to send to the server themselves such as through a gallery selection. Also, I do NOT want to send multiple images to the server--just one random, unknown, non-user selected contained within the captured image directory.
I did a lot of research on this website as well as on numerous other educational websites. I noticed that Android's built-in Random class would be of great use.
Upon greater research I wrote some additional code that extends the original camera app code. However, the bitmap is returning null. I logged a bunch of key parts surrounding the bitmap in order to attempt to grasp why, but I do not see the issue.
I appreciate any insight as to why this is occurring and if I seem to be on the right track with my interested feature. I would love to hear additional ways in which to improve my app as you see fit. Thank you so much!
Here is my code:
public class MainActivity extends Activity {
// Activity request codes.
private static final int CAMERA_CAPTURE_IMAGE_REQUEST_CODE = 100;
public static final int MEDIA_TYPE_IMAGE = 1;
Bitmap bitmap;
ProgressDialog pd;
//Directory name to store captured images.
private static final String IMAGE_DIRECTORY_NAME = "Hello Camera";
private Uri fileUri; //File url to store captured images.
private ImageView imgPreview;
private Button btnCapturePicture;
private Button upload;
Button mButton;
EditText mEdit;
/* Initializes activity, defines UI layout, and retrieves widgets
* to interact with.
* @param savedInstanceState - data is caught here and saved for
* future app use.
*/
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
mButton = (Button)findViewById(R.id.button);
mEdit = (EditText)findViewById(R.id.edittext);
mButton.setOnClickListener(new View.OnClickListener() {
public void onClick(View view) {
Log.v("EditText", mEdit.getText().toString());
}
});
imgPreview = (ImageView) findViewById(R.id.imgPreview);
btnCapturePicture = (Button) findViewById(R.id.btnCapturePicture);
upload = (Button) findViewById(R.id.upload);
upload.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
// TODO Auto-generated method stub
if (bitmap == null) {
Toast.makeText(getApplicationContext(), "Please Select Image", Toast.LENGTH_LONG).show();
} else {
new ImageUpload().execute();
}
}
});
/**
* Captures image button click event in order to capture a photo.
* @param new View.OnClickListener- call to constructor
*/
btnCapturePicture.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
//Captures an image.
captureImage();
}
});
//Checks for camera availability.
if (!isDeviceSupportCamera()) {
Toast.makeText(getApplicationContext(),
"Sorry! Your device doesn't support camera", Toast.LENGTH_LONG).show();
//Closes if a camera is not available on the device.
finish();
}
}
/**
* Checks if device has camera hardware.
*
* @return - true or false.
*/
private boolean isDeviceSupportCamera() {
if (getApplicationContext().getPackageManager().hasSystemFeature(PackageManager.FEATURE_CAMERA)) {
//Device has a camera.
return true;
} else {
// Device does not have a camera.
return false;
}
}
/*
* Launches camera app request image capture.
*/
private void captureImage() {
Intent intent = new Intent(MediaStore.ACTION_IMAGE_CAPTURE);
fileUri = getOutputMediaFileUri(MEDIA_TYPE_IMAGE);
intent.putExtra(MediaStore.EXTRA_OUTPUT, fileUri);
//Starts the image capture Intent.
startActivityForResult(intent, CAMERA_CAPTURE_IMAGE_REQUEST_CODE);
}
/**
* Gets and stores the file url. Will be null after returning from camera
* app.
*
* @param outState - Holds per-instance state from activity.
*/
@Override
protected void onSaveInstanceState(Bundle outState) {
super.onSaveInstanceState(outState);
// Saves the file url in bundle. It will be null on screen orientation changes.
outState.putParcelable("file_uri", fileUri);
}
@Override
protected void onRestoreInstanceState(Bundle savedInstanceState) {
super.onRestoreInstanceState(savedInstanceState);
//Gets the file url.
fileUri = savedInstanceState.getParcelable("file_uri");
}
/**
* Receives activity result method. Will be called after closing the camera.
*
* @param requestCode - Requests to capture an image.
* @param resultCode - Based on success or failure of image capturing, shows
* an image preview or one of two error messages.
* @param data - Carries the result data(successfully captured image).
* @return - An image preview, or one of two error messages.
*/
@Override
protected void onActivityResult(int requestCode, int resultCode, Intent data) {
//If the result is the image capturing event,
if (requestCode == CAMERA_CAPTURE_IMAGE_REQUEST_CODE) {
if (resultCode == RESULT_OK) {
//the image was successfully captured
// and will be displayed in the preview.
previewCapturedImage();
} else if (resultCode == RESULT_CANCELED) {
//The user cancelled the image capturing.
Toast.makeText(getApplicationContext(),
"User cancelled image capture", Toast.LENGTH_SHORT).show();
} else {
//Image capturing failed, but the user did not actually cancel it.
Toast.makeText(getApplicationContext(),
"Sorry! Failed to capture image", Toast.LENGTH_SHORT).show();
}
}
}
/**
* Displays the image from a path to ImageView.
* Downsizes an image if necessary and throws exception
* if the image is too large.
*/
private void previewCapturedImage() {
try {
imgPreview.setVisibility(View.VISIBLE);
upload.setVisibility(View.VISIBLE);
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
IMAGE_DIRECTORY_NAME);
Log.v("Directory", mediaStorageDir.toString());
mediaStorageDir.listFiles(new FileFilter() {
public boolean accept(File file) {
return !file.isDirectory();
}
});
File[] listFiles = mediaStorageDir.listFiles();
Log.v("File listFiles", listFiles.toString());
Random r = new Random ();
Log.v("Random r", r.toString());
File randomPicture = listFiles[r.nextInt(listFiles.length)];
Log.v("Random Picture File", randomPicture.toString());
Uri fileUri = Uri.fromFile(randomPicture);
Log.v("fileUri", fileUri.toString());
BitmapFactory.Options options = new BitmapFactory.Options();
// Downsizes images. Will throw OutOfMemory Exception for larger images.
options.inSampleSize = 8;
Bitmap bitmap = BitmapFactory.decodeFile(fileUri.getPath(), options);
Log.v("Bitmap", bitmap.toString());
ImageView imgView = (ImageView) findViewById(R.id.imgPreview);
Log.v("ImgView", imgView.toString());
imgView.setImageBitmap(BitmapFactory.decodeFile(fileUri.getPath()));
} catch (NullPointerException e) {
e.printStackTrace();
}
}
/**
* Creates the file uri to store an image.
*
* @param type - Refers to the captured image.
* @return Uri.fromFile - The file uri to store an image.
*/
public Uri getOutputMediaFileUri(int type) {
return Uri.fromFile(getOutputMediaFile(type));
}
/**
* Returns the captured image.
*
* @param type - Refers to the captured image.
* @return null or mediaFile - mediaFile: Captured
* image inside of timestamped file.
*/
private static File getOutputMediaFile(int type) {
// External sdcard location.
File mediaStorageDir = new File(Environment.getExternalStoragePublicDirectory(Environment.DIRECTORY_PICTURES),
IMAGE_DIRECTORY_NAME);
Log.v("Directory Two", mediaStorageDir.toString());
// Create the storage directory if it does not exists
if (!mediaStorageDir.exists()) {
if (!mediaStorageDir.mkdirs()) {
Log.d(IMAGE_DIRECTORY_NAME, "Oops! Failed create " + IMAGE_DIRECTORY_NAME + " directory");
return null;
}
}
// Creates a media file name corresponding to a timestamp.
String timeStamp = new SimpleDateFormat("yyyyMMdd_HHmmss", Locale.getDefault()).format(new Date());
File mediaFile;
if (type == MEDIA_TYPE_IMAGE) {
mediaFile = new File(mediaStorageDir.getPath() + File.separator + "IMG_" + timeStamp + ".jpg");
} else {
return null;
}
Log.v("MediaFile", mediaFile.toString());
return mediaFile;
}
/*
* Uploads the saved and captured image to the server.
*/
public class ImageUpload extends AsyncTask<String, String,String> {
String postUrl = "";
public void postURL(String url) {
postUrl = url;
}
/**
* Compresses the selected gallery image and encodes
* compressed image to a base64 string.
*
* @param params
*/
@Override
protected String doInBackground(String... params) {
String result = null;
try {
HttpClient client = new DefaultHttpClient();
String postURL = "";
HttpPost post = new HttpPost("http://ift.tt/1J0913I");
ArrayList<NameValuePair> nameValuePair = new ArrayList<NameValuePair>();
String msg = mEdit.getText().toString();
nameValuePair.add(new BasicNameValuePair("carid",msg));
//Converts image file uri to blob base64
ByteArrayOutputStream stream = new ByteArrayOutputStream();
bitmap.compress(Bitmap.CompressFormat.PNG, 90, stream);
byte[] byte_arr = stream.toByteArray();
Log.v("ByteArray Stream", stream.toString());
Log.v("byte from stream", byte_arr.toString());
String image_str = new String(Base64.encode(byte_arr, Base64.DEFAULT));
nameValuePair.add(new BasicNameValuePair("carimage", image_str));
UrlEncodedFormEntity ent = new UrlEncodedFormEntity(nameValuePair, HTTP.UTF_8);
post.setEntity(ent);
HttpResponse responsePOST = client.execute(post);
HttpEntity resEntity = responsePOST.getEntity();
result = EntityUtils.toString(resEntity);
if (resEntity != null) {
Log.i("RESPONSE", EntityUtils.toString(resEntity));
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
@Override
protected void onPostExecute(String result) {
if (result != null) {
Toast.makeText(getApplicationContext(),
"Successfully uploaded", Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getApplicationContext(),
"Sorry! Failed to upload", Toast.LENGTH_SHORT).show();
}
}
}
}
Manifest:
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://ift.tt/nIICcg"
package="com.example.justin.myapplication" >
android:versionCode="1"
android:versionName="1.0" >
<uses-sdk
android:minSdkVersion="11"
android:targetSdkVersion="22" />
<supports-screens
android:largeScreens="true"
android:normalScreens="true"
android:smallScreens="true"
android:anyDensity="true">
</supports-screens>
<!-- Accessing camera hardware -->
<uses-feature android:name="android.hardware.camera" />
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.CAMERA" />
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-feature android:name="android.hardware.screen.portrait" />
<uses-permission android:name="android.permission.ACCESS_WIFI_STATE"/>
<uses-permission android:name="android.permission.READ_EXTERNAL_STORAGE" />
<application
android:allowBackup="true"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".MainActivity"
android:label="@string/app_name"
android:configChanges="orientation|keyboard|keyboardHidden"
android:screenOrientation="portrait">
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
</manifest>
Logcat:
07-15 16:07:36.531 22150-22150/com.example.justin.myapplication D/dalvikvm﹕ Late-enabling CheckJNI
07-15 16:07:36.664 22150-22150/com.example.justin.myapplication D/libEGL﹕ loaded /vendor/lib/egl/libEGL_POWERVR_SGX540_120.so
07-15 16:07:36.664 22150-22150/com.example.justin.myapplication D/libEGL﹕ loaded /vendor/lib/egl/libGLESv1_CM_POWERVR_SGX540_120.so
07-15 16:07:36.672 22150-22150/com.example.justin.myapplication D/libEGL﹕ loaded /vendor/lib/egl/libGLESv2_POWERVR_SGX540_120.so
07-15 16:07:36.742 22150-22150/com.example.justin.myapplication D/OpenGLRenderer﹕ Enabling debug mode 0
07-15 16:07:43.961 22150-22150/com.example.justin.myapplication V/EditText﹕ 5
07-15 16:07:45.781 22150-22150/com.example.justin.myapplication V/Directory Two﹕ /storage/emulated/0/Pictures/Hello Camera
07-15 16:07:45.789 22150-22150/com.example.justin.myapplication V/MediaFile﹕ /storage/emulated/0/Pictures/Hello Camera/IMG_20150715_160745.jpg
07-15 16:07:46.484 22150-22150/com.example.justin.myapplication W/IInputConnectionWrapper﹕ showStatusIcon on inactive InputConnection
07-15 16:07:52.859 22150-22150/com.example.justin.myapplication V/Directory﹕ /storage/emulated/0/Pictures/Hello Camera
07-15 16:07:52.906 22150-22150/com.example.justin.myapplication V/File listFiles﹕ [Ljava.io.File;@4276b448
07-15 16:07:52.906 22150-22150/com.example.justin.myapplication V/Random r﹕ java.util.Random@42777f30
07-15 16:07:52.906 22150-22150/com.example.justin.myapplication V/Random Picture File﹕ /storage/emulated/0/Pictures/Hello Camera/IMG_20150710_160840.jpg
07-15 16:07:52.906 22150-22150/com.example.justin.myapplication V/fileUri﹕ file:///storage/emulated/0/Pictures/Hello%20Camera/IMG_20150710_160840.jpg
07-15 16:07:52.937 22150-22150/com.example.justin.myapplication D/dalvikvm﹕ GC_FOR_ALLOC freed 187K, 3% free 8776K/9000K, paused 14ms, total 15ms
07-15 16:07:53.242 22150-22150/com.example.justin.myapplication V/Bitmap﹕ android.graphics.Bitmap@42754638
07-15 16:07:53.242 22150-22150/com.example.justin.myapplication V/ImgView﹕ android.widget.ImageView{42747f90 V.ED.... ......I. 0,0-0,0 #7f0c0051 app:id/imgPreview}
07-15 16:07:53.265 22150-22150/com.example.justin.myapplication D/dalvikvm﹕ GC_FOR_ALLOC freed 38K, 3% free 9080K/9308K, paused 14ms, total 14ms
07-15 16:07:53.359 22150-22150/com.example.justin.myapplication I/dalvikvm-heap﹕ Grow heap (frag case) to 28.113MB for 20155408-byte allocation
07-15 16:07:53.383 22150-22159/com.example.justin.myapplication D/dalvikvm﹕ GC_FOR_ALLOC freed <1K, 1% free 28763K/28992K, paused 19ms, total 19ms
07-15 16:07:53.398 22150-22153/com.example.justin.myapplication D/dalvikvm﹕ GC_CONCURRENT freed <1K, 1% free 28763K/28992K, paused 3ms+2ms, total 20ms
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