showing image in imageview using thread

Question

hi every body im aymen and im student im creating an application who shows the image downloaded from ftp server which was token by the webcam
i wanna refresh the pic every 2 seconds but i didnt succeed even with one time plz help this is my code until now **mainActivity**

package com.pfe.ftpstreamer;

import java.io.FileOutputStream;

import com.pfe.ftpstreamer.R;
import com.pfe.ftpstreamer.MyFTPClient;

import android.os.Bundle;
import android.app.Activity;
import android.content.Context;
import android.graphics.BitmapFactory;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.ImageView;

public class MainActivity extends Activity implements OnClickListener {
private static final String TAG = "MainActivity";
private static final String TEMP_FILENAME = "test.txt";
private static final String TEMP_FILENAME1 = "cam.jpg";
private Context cntx = null;

MyFTPClient ftpclient = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    cntx = this.getBaseContext();

    View startButton = findViewById(R.id.button1);
    startButton.setOnClickListener(this);
    View stopButton = findViewById(R.id.button2);
    stopButton.setOnClickListener(this);
    View exitButton = findViewById(R.id.button3);
    exitButton.setOnClickListener(this);
 // Create a temporary file. You can use this to upload
    createDummyFile();
    ftpclient = new MyFTPClient();
}
public void onClick(View v) {
    switch(v.getId()) {
    case R.id.button1:
        new Thread(new Runnable() {
            public void run(){
                boolean status = false;
                // Replace your UID & PW here
                status = ftpclient.ftpConnect("192.168.1.1", "Administrator", "12345", 21);
                if (status == true) {
                    Log.d(TAG, "Connection Success");
                    status = ftpclient.ftpUpload(TEMP_FILENAME, TEMP_FILENAME, "/", cntx);
                    //downloading file
                    ftpclient.ftpDownload(TEMP_FILENAME1,getFilesDir() + "/" +TEMP_FILENAME1);
                    //removing the file from server 
                    ftpclient.ftpRemoveFile(TEMP_FILENAME1);
                    //showing the file in the ImageView
                    new Thread(new Runnable() {
                        public void run(){
                            ImageView imgView = (ImageView) findViewById(R.id.imageView1);
                            imgView.setImageBitmap(BitmapFactory.decodeFile(getFilesDir() + "/" +TEMP_FILENAME1));
                        }
                    }).start();



                } else {
                    //Toast.makeText(getApplicationContext(), "Connection failed", 2000).show();
                    Log.d(TAG, "Connection failed");
                }
            }
        }).start();
        break;  
    case R.id.button2:
        new Thread(new Runnable() {
            public void run(){
                ftpclient.ftpDisconnect();
            }
        }).start();

        break;
    case R.id.button3:
        this.finish();
        break;
    }

}

public void createDummyFile() {
    try {
        FileOutputStream fos;
        String file_content = "Hi this is a sample file to upload for android FTP client example";

        fos = openFileOutput(TEMP_FILENAME, MODE_PRIVATE);
        fos.write(file_content.getBytes());
        fos.close();

    } catch (Exception e) {
        e.printStackTrace();
    }

}

@Override
public boolean onCreateOptionsMenu(Menu menu) {
    // Inflate the menu; this adds items to the action bar if it is present.
    getMenuInflater().inflate(R.menu.main, menu);
    return true;
}}

*myftpclient**

package com.pfe.ftpstreamer;
import java.io.BufferedInputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;

import org.apache.commons.net.ftp.*;

import android.content.Context;
import android.util.Log;

public class MyFTPClient {



//Now, declare a public FTP client object.

private static final String TAG = "MyFTPClient";
public FTPClient mFTPClient = null; 

//Method to connect to FTP server:
public boolean ftpConnect(String host, String username ,
                          String password, int port)
{
    try {
        mFTPClient = new FTPClient();
        // connecting to the host
        mFTPClient.connect(host, port);

        // now check the reply code, if positive mean connection success
        if (FTPReply.isPositiveCompletion(mFTPClient.getReplyCode())) {
            // login using username & password
            boolean status = mFTPClient.login(username, password);

            /* Set File Transfer Mode
             *
             * To avoid corruption issue you must specified a correct
             * transfer mode, such as ASCII_FILE_TYPE, BINARY_FILE_TYPE,
             * EBCDIC_FILE_TYPE .etc. Here, I use BINARY_FILE_TYPE
             * for transferring text, image, and compressed files.
             */
            mFTPClient.setFileType(FTP.BINARY_FILE_TYPE);
            mFTPClient.enterLocalPassiveMode();

            return status;
        }
    } catch(Exception e) {
        Log.d(TAG, "Error: could not connect to host " + host );
    }

    return false;
} 

//Method to disconnect from FTP server:

public boolean ftpDisconnect()
{
    try {
        mFTPClient.logout();
        mFTPClient.disconnect();
        return true;
    } catch (Exception e) {
        Log.d(TAG, "Error occurred while disconnecting from ftp server.");
    }

    return false;
} 

//Method to get current working directory:



//Method to change working directory:



//Method to list all files in a directory:



//Method to create new directory:



//Method to delete/remove a directory:



//Method to delete a file:

public boolean ftpRemoveFile(String filePath)
{
    try {
        boolean status = mFTPClient.deleteFile(filePath);
        return status;
    } catch (Exception e) {
        e.printStackTrace();
    }

    return false;
} 

//Method to rename a file:



//Method to download a file from FTP server:

/**
 * mFTPClient: FTP client connection object (see FTP connection example)
 * srcFilePath: path to the source file in FTP server
 * desFilePath: path to the destination file to be saved in sdcard
 */
public boolean ftpDownload(String srcFilePath, String desFilePath)
{
    boolean status = false;
    try {
        FileOutputStream desFileStream = new FileOutputStream(desFilePath);;
        status = mFTPClient.retrieveFile(srcFilePath, desFileStream);
        desFileStream.close();

        return status;
    } catch (Exception e) {
        Log.d(TAG, "download failed");
    }

    return status;
} 

//Method to upload a file to FTP server:

/**
 * mFTPClient: FTP client connection object (see FTP connection example)
 * srcFilePath: source file path in sdcard
 * desFileName: file name to be stored in FTP server
 * desDirectory: directory path where the file should be upload to
 */
public boolean ftpUpload(String srcFilePath, String desFileName,
                         String desDirectory, Context context)
{
    boolean status = false;
    try {
       // FileInputStream srcFileStream = new FileInputStream(srcFilePath);

        FileInputStream srcFileStream = context.openFileInput(srcFilePath);

        // change working directory to the destination directory
        //if (ftpChangeDirectory(desDirectory)) {
            status = mFTPClient.storeFile(desFileName, srcFileStream);
        //}

        srcFileStream.close();
        return status;
    } 
    catch (Exception e) {
        Log.d(TAG, "upload failed: " + e);
    }

    return status;
}
}

Answer 1

You should check that image is downloaded or not, if its downloaded then you can update your UI in ui thread i.e.

mainActivity.this.runOnUiThread(new Runnable() {
    public void run() {
        ImageView imgView = (ImageView) findViewById(R.id.imageView1);
       imgView.setImageBitmap(BitmapFactory.decodeFile(getFilesDir() + "/" +TEMP_FILENAME1));
      }
}

Answer 2

Ok, your problem is, that you are not in the UI-Thread.

You could use a AsyncTask or a Handler, which updates your view or layout.

Check this out: update-ui-from-thread

Answer 3

You can't update Your Ui direct from your thread use handler for that purpose check this link