Printing coordinates from an array in Android

Question

I'm working on an image processing application that analyzes ECG graph. To do so, I need to detect certain peaks of the graph.

How can I print the "coordinates", "xcoor" and "ycoor" in the user interface? I tried toasting it but it doesn't work. I tried textView but the application force closes.

package com.thesis.results;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.graphics.Color;
import android.os.Bundle;
import android.os.Handler;
import android.view.View;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.TextView;
import java.util.ArrayList;
import android.widget.Toast;


import com.example.edgedetection.R;

public class MainActivity extends Activity {

    // initialize variables
    static int i = 0;
    static int bl_ = 0; // number of black; pixels in the image
    static int op_ = 0;
    static int Al = 0;
    static int Re = 0;
    static int Gr = 0;
    static int Bl = 0;
    static int Alp = 0;
    static int Red = 0;
    static int Gre = 0;
    static int Blu = 0;
    static int stop = 0;
    static int stopx = 0;
    static int stopy = 1000;
    static int xcoor[];
    static int ycoor[];
    static int width;
    static int height;
    static int RRdistance;
    static double voltage;
    static int peakcoordinates;

    ImageView imageSource, imageAfter;
    Bitmap bitmap_Source;
    ProgressBar progressBar;
    Button process;
    TextView counter;
    TextView coordinates;
    private Handler handler;
    Bitmap afterProcess;

    /** Called when the activity is first created. */
    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        process = (Button) findViewById(R.id.btn_process);
        imageSource = (ImageView) findViewById(R.id.imageSource);
        imageAfter = (ImageView) findViewById(R.id.imageAfter);
        progressBar = (ProgressBar) findViewById(R.id.progressBar);
        counter = (TextView) findViewById(R.id.counter);
        coordinates = (TextView) findViewById(R.id.coordinates);

        process.setOnClickListener(new View.OnClickListener() {

            public void onClick(View v) {
                // TODO Auto-generated method stub
                bitmap_Source = BitmapFactory.decodeResource(getResources(),
                        R.drawable.test_ideal_graph);
                handler = new Handler();
                StratBackgroundProcess();
            }
        });

    }

    private void StratBackgroundProcess() {

        Runnable runnable = new Runnable() {

            public void run() {
                afterProcess = processingBitmap(bitmap_Source, 0, 0, 0);

                handler.post(new Runnable() {

                    public void run() {
                        progressBar.setVisibility(View.GONE);
                        imageAfter.setImageBitmap(afterProcess);

                        calculatevoltage();
                        //  calculateRRdistance();
                        counter.setText("" + bl_ + "@ (" + stopx + "," + stopy
                                + " " + "and" + 
                                ")" + " {" + width + "," + height + " } = "
                                        + voltage + "mV" + " " + "R-R distance:" + " "
                                        + RRdistance);

                        coordinates.setText(" " + xcoor + "," + ycoor + " " );
                    }

                    private void calculatevoltage() {
                        // TODO Auto-generated method stub
                        voltage = ((0.1 * height) * (height - stopy)) / height;
                        // 1.5 mV is the total voltage of the graph, 1 box =
                        // 0.1mV
                    }

                    //private void calculateRRdistance() {
                    // TODO Auto-generated method stub
                    //     RRdistance = stopx1 - stopx;
                    // 1.5 mV is the total voltage of the graph, 1 box =
                    // 0.1mV

                    //   }

                });
            }
        };
        new Thread(runnable).start();
    }

    public static Bitmap processingBitmap(Bitmap src, double red, double green,
            double blue) {
        // image size
        width = src.getWidth();
        height = src.getHeight();
        // create output bitmap
        Bitmap bmOut = Bitmap.createBitmap(width, height, src.getConfig());
        // color information
        int A, R, G, B;
        int pixel;
        int flag = 0;

        //array
        int[] trial = new int[width];
        // scan through all pixels

        for (int x = 0; x < width; ++x) {

            flag = 0;

            for (int y = 0; y < height; ++y) {
                // get pixel color
                pixel = src.getPixel(x, y);
                // apply filtering on each channel R, G, B
                Al = Color.alpha(pixel);
                Re = (int) (Color.red(pixel));
                Gr = (int) (Color.green(pixel));
                Bl = (int) (Color.blue(pixel));
                // set new color pixel to output bitmap

                if ((Re == 0) && (Gr == 0) && (Bl == 0) && (flag == 0)) {
                    bmOut.setPixel(x, y, Color.argb(255, 0, 0, 0));
                    flag = 1;
                    trial[x] = y;

                } else
                    bmOut.setPixel(x, y, Color.argb(255, 255, 255, 255));

            }
        }

        //detect all possible peaks

        for (int x = 1; x < width; x++) {
            if (trial[x] < trial[x - 1] && trial[x] < trial[x + 1]) {
                peakcoordinates = src.getPixel(x, trial[x]); //get pixels, how to display? (textview, toast?)
                //Toast.makeText(getApplicationContext(), "hi", Toast.LENGTH_LONG).show();
            }

            //detect all R peaks
            for (int y = 1; y > (trial[1]-50); y++ ){

                xcoor[i] = x;
                ycoor[i] = y;
            }
            return bmOut;
        }
        return bmOut;
    }
}

When I add the line coordinates.setText(" " + xcoor + "," + ycoor + " " );, the application fails to launch. — cookie23, Feb 22 '13 at 08:46

score 0 · Answer 1 · answered Feb 22 '13 at 08:50

0

Your application crashes because you're trying to access your Views from a worker thread, which is prohibited in Android. I'd recommend using the AsyncTask class, which runs a certain task on a worker thread and provides methods that run on UI thread, where you can update your Views. Hope this helps.

answered Feb 22 '13 at 08:50

Egor

39,695
10
113
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Views? Sorry but I am kinda new to Android programming. I am not familiar with Views or AsyncTask. :( – cookie23 Feb 22 '13 at 08:53
If you want to update your textview or show a toast message or other updates to the UI, you cannot do it from the Runnable's run method. Check this stackoverflow question: [AsyncTask](http://stackoverflow.com/questions/9671546/asynctask-android-example) – faceman Feb 22 '13 at 09:14

score 0 · Answer 2 · answered Feb 22 '13 at 09:11

You can modify your view (something like TextView, ImageView) only in UI thread. Try AsyncTask:

@Override
public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        process = (Button) findViewById(R.id.btn_process);
        imageSource = (ImageView) findViewById(R.id.imageSource);
        imageAfter = (ImageView) findViewById(R.id.imageAfter);
        progressBar = (ProgressBar) findViewById(R.id.progressBar);
        counter = (TextView) findViewById(R.id.counter);
        coordinates = (TextView) findViewById(R.id.coordinates);

        process.setOnClickListener(new View.OnClickListener() {

                public void onClick(View v) {
                        // TODO Auto-generated method stub
                        bitmap_Source = BitmapFactory.decodeResource(getResources(),
                                        R.drawable.test_ideal_graph);
                        handler = new Handler();
                        new BackgroundTask().execute();
                }
        });

}

private class BackgroundTask extends AsyncTask<String, Long, String> {

    @Override
    protected String doInBackground(String... s) {
        afterProcess = processingBitmap(bitmap_Source, 0, 0, 0);
        return null;
    }

    @Override
    protected void onPostExecute(String result) {
        progressBar.setVisibility(View.GONE);
        imageAfter.setImageBitmap(afterProcess);

        calculatevoltage();
        //  calculateRRdistance();
        counter.setText("...");
        coordinates.setText(" " + xcoor + "," + ycoor + " " );
    }
}

I tried doing this but it still does not launch. What must be in the position of (String... s) ? — cookie23, Feb 22 '13 at 09:23
I copied from my old project, but you don't need to change the code. What's the error message now? — iForests, Feb 22 '13 at 09:33
It does not have an error but it fails to launch. I don't understand why and I'm getting frustrated. :(( — cookie23, Feb 22 '13 at 09:35
Can you send your project to my email? I will check it later. — iForests, Feb 22 '13 at 09:49

Printing coordinates from an array in Android

2 Answers2