Develop Reference

Bitmap saved as black image sometimes for same bitmap

I know this was a common issue, but I have tried different suggestion, and still no solution.
My issue is that the bitmap is being displayed correctly, however SOMETIMES it saves as a black bitmap, while other times it saves correctly.
Can anyone see what I have done and tell me where I can be going wrong?
I have looked at most of the other StackOverflow questions.
The following is my code, which encodes the clip board text into a QR code and attempts to save the qr code generated.
Thank you!
import android.content.Context;
import android.content.Intent;
import android.graphics.Bitmap;
import android.net.Uri;
import android.os.Bundle;
import android.os.Environment;
import android.support.v7.app.AppCompatActivity;
import android.text.ClipboardManager;
import android.view.View;
import android.widget.ImageView;
import android.widget.TextView;
import android.widget.Toast;
import com.nostra13.universalimageloader.core.DisplayImageOptions;
import com.nostra13.universalimageloader.core.ImageLoader;
import com.nostra13.universalimageloader.core.ImageLoaderConfiguration;
import java.io.File;
import java.io.FileOutputStream;
import java.io.UnsupportedEncodingException;
import java.net.URLEncoder;
//import android.content.ClipboardManager;
public class BarcodeWriter extends AppCompatActivity {
ImageLoader imgLoader;
ImageView qrImg;
String copiedStr;
TextView qrTxt;
ClipboardManager clipboard;
String BASE_QR_URL = "http://chart.apis.google.com/chart?cht=qr&chs=400x400&chld=M&choe=UTF-8&chl=";
String fullUrl = BASE_QR_URL;
#Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.barcode_writer);
DisplayImageOptions defaultOptions = new DisplayImageOptions.Builder()
.cacheInMemory(true)
.cacheOnDisk(true)
.build();
ImageLoaderConfiguration config = new ImageLoaderConfiguration.Builder(getApplicationContext())
.defaultDisplayImageOptions(defaultOptions)
.build();
imgLoader = ImageLoader.getInstance(); // Do it on Application start
imgLoader.init(config);
qrImg = (ImageView)findViewById(R.id.qrImg);
qrTxt = (TextView)findViewById(R.id.qrTxt);
clipboard = (ClipboardManager)getSystemService(Context.CLIPBOARD_SERVICE);
/*
* clipboard.getText() is now deprecated. But I am going to use it here
* because the new way of doing the same thing only works on API lvl 11+
* Since I want this application to support API lvl 4+ we have to use
* the old method.
*/
CharSequence clipTxt = clipboard.getText();
//This is the new, non-deprecated way of getting text from the Clipboard.
//CharSequence clipTxt = clipboard.getPrimaryClip().getItemAt(0).getText();
//If the clipboard has text, and it is more than 0 characters.
if((null != clipTxt) && (clipTxt.length() > 0)){
try {
qrTxt.setText(clipTxt);
copiedStr = clipTxt.toString();
fullUrl += URLEncoder.encode(copiedStr, "UTF-8");
//imgLoader.displayImage(fullUrl, qrImg);
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions); // Incoming options will be used
qrImg.setDrawingCacheEnabled(true);
qrImg.measure(View.MeasureSpec.makeMeasureSpec(100, View.MeasureSpec.EXACTLY),
View.MeasureSpec.makeMeasureSpec(100, View.MeasureSpec.EXACTLY));
qrImg.layout(0, 0, qrImg.getMeasuredWidth(), qrImg.getMeasuredHeight());
qrImg.buildDrawingCache();
Bitmap bm = Bitmap.createBitmap(qrImg.getDrawingCache());
qrImg.setDrawingCacheEnabled(false); // clear drawing cache
try {
String root = Environment.getExternalStorageDirectory().toString();
File myDir = new File(root + "/DCIM/QR codes");
myDir.mkdirs();
String fname = clipTxt+".png";
File file = new File (myDir, fname);
if (file.exists ()) file.delete ();
try {
FileOutputStream out = new FileOutputStream(file);
bm.compress(Bitmap.CompressFormat.PNG, 100, out);
Toast.makeText(BarcodeWriter.this, "Image Saved", Toast.LENGTH_SHORT).show();
out.flush();
out.close();
} catch (Exception e) {
e.printStackTrace();
}
Intent mediaScanIntent = new Intent(Intent.ACTION_MEDIA_SCANNER_SCAN_FILE);
Uri contentUri = Uri.fromFile(file);
mediaScanIntent.setData(contentUri);
getApplicationContext().sendBroadcast(mediaScanIntent);
Toast.makeText(this,"QR Code showing "+clipTxt,Toast.LENGTH_SHORT).show();
} catch (Exception e) {
Toast.makeText(this, "Error occurred. Please try again later.",
Toast.LENGTH_SHORT).show();
}
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}else{ //If no text display a dialog.
Toast.makeText(this,"No text in clipboard",Toast.LENGTH_SHORT).show();
}
}
}

Your code seems to be fine, the only thing that I saw is that you are getting you Bitmap from and external URL with Universal Image Loader instantly after calling displayImage. So is possible that for some delay in the network sometimes your ImageView still doesn't have the entire image and can make your bitmap saved as black.
Please try moving your all code bellow ImageLoader.getInstance().displayImage inside the onLoadingComplete like this:
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions, new SimpleImageLoadingListener()
{
#Override
public void onLoadingComplete(String imageUri, View view, Bitmap loadedImage) {
ImageLoader.getInstance().displayImage(fullUrl, qrImg, defaultOptions,null);
qrImg.setDrawingCacheEnabled(true);
...
catch (Exception e) {
Toast.makeText(this, "Error occurred. Please try again later.",
Toast.LENGTH_SHORT).show();
}
}
});
Hope this help!!

How to read whatsapp message from notification extras

Hi I'm working on an app in which I have to read images from whatsapp. I can read the first image as a bitmap with this line of code:
Bitmap btm = (Bitmap) sbn.getNotification().extras.get(Notification.EXTRA_PICTURE);
The problem is that if I receive more than one images I get null. How can I resolve this?

this is the NotificationListenerService:
package com.etaure.callany.testwhatsappimage;
import android.accounts.AccountManager;
import android.app.Notification;
import android.content.Intent;
import android.graphics.Bitmap;
import android.service.notification.NotificationListenerService;
import android.service.notification.StatusBarNotification;
import android.support.annotation.Nullable;
import android.support.v4.content.LocalBroadcastManager;
import android.text.TextUtils;
import android.util.Log;
import org.json.JSONArray;
/**
* Created by administrator on 03/11/2015.
*/
public class MyNotificationListner extends NotificationListenerService {
static int i = 0;
#Override
public void onNotificationPosted(StatusBarNotification sbn) {
if (sbn.getPackageName().equals("com.whatsapp")) {
Bitmap btm = (Bitmap) sbn.getNotification().extras.get(Notification.EXTRA_PICTURE);
}
}
#Override
public void onNotificationRemoved(StatusBarNotification sbn) {
Log.w("Test", "NotificationRemoved");
}
}

this is a code that parses for you whatsapp images and shows ( if you want ) on your logcat all base64 string! Enjoy
`
if (extras.containsKey(Notification.EXTRA_PICTURE)) {
bmp = (Bitmap) extras.get(Notification.EXTRA_PICTURE);
ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.PNG, 100, byteArrayOutputStream);
byteArrayS = byteArrayOutputStream .toByteArray();
encoded = Base64.encodeToString(byteArrayS, Base64.DEFAULT);
final int LOGCAT_MAX_LENGTH = 3950;
if (BuildConfig.DEBUG) {
while (encoded.length() > LOGCAT_MAX_LENGTH) {
int substringIndex = encoded.lastIndexOf(",", LOGCAT_MAX_LENGTH);
if (substringIndex == -1)
substringIndex = LOGCAT_MAX_LENGTH;
Log.d("encode", encoded.substring(0, substringIndex));
encoded = encoded.substring(substringIndex).trim();
}
Log.d("encode", encoded);
}
}
`

how to send data (a string) to a paired device in android?

I am working on bluetooth for the first time. I got the list of paired devices. Now my requirement is I need to send some data (a string) to the device. how can I do that? I tried searching but didn't find anything useful. Could anyone help out this?

Something like this might suffice:
DataOutputStream os;
BluetoothAdapter bluetooth = BluetoothAdapter.getDefaultAdapter();
BroadcastReceiver discoveryResult = new BroadcastReceiver() {
public void onReceive(Context context, Intent intent) {
String remoteDeviceName = intent.getStringExtra(BluetoothDevice.EXTRA_NAME);
BluetoothDevice remoteDevice;
remoteDevice = intent.getParcelableExtra(BluetoothDevice.EXTRA_DEVICE);
Toast.makeText(getApplicationContext(), "Discovered: " + remoteDeviceName + " address " + remoteDevice.getAddress(), Toast.LENGTH_SHORT).show();
try{
BluetoothDevice device = bluetooth.getRemoteDevice(remoteDevice.getAddress());
Method m = device.getClass().getMethod("createRfcommSocket", new Class[] {int.class});
BluetoothSocket clientSocket = (BluetoothSocket) m.invoke(device, 1);
clientSocket.connect();
os = new DataOutputStream(clientSocket.getOutputStream());
new clientSock().start();
} catch (Exception e) {
e.printStackTrace();
Log.e("BLUETOOTH", e.getMessage());
}
}
};
registerReceiver(discoveryResult, new IntentFilter(BluetoothDevice.ACTION_FOUND));
bluetooth.enable();
if (!bluetooth.isDiscovering()) {
bluetooth.startDiscovery();
}
public class clientSock extends Thread {
public void run () {
try {
os.writeBytes("anything you want"); // anything you want
os.flush();
} catch (Exception e1) {
e1.printStackTrace();
return;
}
}
}
You will also need a lot of imports such as these:
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.lang.reflect.Method;
import java.net.ServerSocket;
import java.net.Socket;
import java.net.UnknownHostException;
import java.util.List;
import java.util.UUID;
import android.os.Bundle;
import android.os.StrictMode;
import android.app.Activity;
import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.util.Log;
import android.view.Menu;
import android.widget.Toast;
note that not all imports are necessary for this example code, your IDE might help you to sort them out for you.
Pass data on the os.writeBytes("anything you want"); // anything you want line.
You will also need Permissions

Sceenshot View have some error: Layout cannot be found

i try to sceenshot View but R.id.layout cannot be resolved or is not a field
and i try to import com.example.mye_card.R; then clean up but not work
btnsave.setOnClickListener(new OnClickListener() {
public void onClick(View v) {
View v2 = findViewById(R.id.layout);
v2.setDrawingCacheEnabled(true);
Bitmap bmp = Bitmap.createBitmap(v2.getDrawingCache());
v2.setDrawingCacheEnabled(false);
try {
Date d = new Date();
String filename = (String)DateFormat.format("kkmmss-MMddyyyy"
, d.getTime());
File dir = new File(Environment.getExternalStorageDirectory(), "/Pictures/" + filename );
FileOutputStream out = new FileOutputStream(dir);
ByteArrayOutputStream bos = new ByteArrayOutputStream();
bmp.compress(Bitmap.CompressFormat.JPEG, 100, bos);
out.write(bos.toByteArray());
Toast.makeText(getApplicationContext(), "Save card!", Toast.LENGTH_SHORT).show();
} catch (FileNotFoundException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
}
});
error line
View v2 = findViewById(R.id.layout);
about import
package com.example.mye_card;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;
import java.util.Date;

The problem probably is because you can't find the ID at the point of the context inside a onClick event.
Go on the top of your .java file, just after the starting of your Class, you probably will see some variables, so create a new variable:
View vDrawing = null;
Then, search for your onCreate method, and declare your variable:
vDrawing = (View) findViewById(R.id.layout);
Now, remove your declaration findViewById() from your onClick event and just use your variable previously declared vDrawing instead of using your v2 variable.

How to generate external logfile in android app?

may i know is there any way to generate external log file?

This can be done e.g. with java.util.logging classes:
import android.os.Environment;
import android.util.Log;
import java.util.logging.FileHandler;
import java.util.logging.Level;
import java.util.logging.LogRecord;
import java.util.logging.SimpleFormatter;
FileHandler fh=null;
String name;
if ( 0 == Environment.getExternalStorageState().compareTo(Environment.MEDIA_MOUNTED))
name = Environment.getExternalStorageDirectory().getAbsolutePath();
else
name = Environment.getDataDirectory().getAbsolutePath();
name += "/mylogfile.log";
try {
fh = new FileHandler(name, 256*1024, 1, true);
fh.setFormatter(new SimpleFormatter());
fh.publish(new LogRecord(level, tag+": "+msg));
} catch (Exception e)
{
Log.e("MyLog", "FileHandler exception", e);
return;
}finally{
if (fh != null)
fh.close();
}