android应用程序做力关闭

Question

I am new to android. I am trying to do some kind of image processing. But I am getting this message "This application --- has stopped unexpectedly. Please try again.". Kindly tell me what mistake I am making

package com.imagep.amit;

import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileOutputStream;
import java.io.IOException;

import android.app.Activity;
import android.graphics.Bitmap;
import android.graphics.Bitmap.CompressFormat;
import android.graphics.BitmapFactory;
import android.os.Bundle;
import android.util.Log;
import android.widget.ImageView;

public class ImagepActivity extends Activity {
    /** Called when the activity is first created. */

    Bitmap myBitmap;
    ImageView myImageView;

    @Override
    public void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.main);
        String imageFileName= "/sdcard/test_vga.jpg";
        File imageFile= new File(imageFileName);
        if (imageFile.exists()) {
            // Load the image from file
            myBitmap= BitmapFactory.decodeFile(imageFileName);
            // Display the image in the image viewer
            myImageView= (ImageView)findViewById(R.id.di);
            if (myImageView!= null) {
                myImageView.setImageBitmap(myBitmap);
            }
        }
        this.processImage();
    }

    private void processImage() {
        brighten(50);
        try {
            String outputPath= "/test_vga_output.jpg";
            int quality = 75;
            FileOutputStream fileOutStr= new FileOutputStream(outputPath);
            BufferedOutputStream bufOutStr= new BufferedOutputStream(fileOutStr);
            myBitmap.compress(CompressFormat.JPEG, quality, bufOutStr);
            bufOutStr.flush();
            bufOutStr.close();
        } catch (FileNotFoundException exception) {
            Log.e("debug_log", exception.toString());
        } catch (IOException exception) {
            Log.e("debug_log", exception.toString());
        }
        myImageView.setImageBitmap(myBitmap);
    }

    private void brighten(int i) {
        int width = myBitmap.getWidth();
        int height = myBitmap.getHeight();
        int[] pix = new int[width * height];
        myBitmap.getPixels(pix, 0, width, 0, 0, width, height);
        // Apply pixel-by-pixel change
        int index = 0;
        for(int y = 0; y < height; y++) {
            for (int x = 0; x < width; x++) {
                int r = (pix[index] >> 16) & 0xff;
                int g = (pix[index] >> 8) & 0xff;
                int b = pix[index] & 0xff;
                r = 0;
                g = 0;
                b = 0;
                pix[index++] = 0xff000000| (r << 16) | (g << 8) | b;
            } // x 
        } // y
        // TODO Auto-generated method stub
    }
}
}

Answer 1

Use adb logcat , DDMS, or the DDMS perspective in Eclipse to examine LogCat and look at the stack trace associated with your error.

In addition, never hardwire paths , particularly since /sdcard is wrong -- use Environment.getExternalStorageDirectory() to get the root of external storage.

Finally, your actual problem probably comes from:

String outputPath= "/test_vga_output.jpg";

which is an invalid path. I do not know where you think you are writing, but you cannot write there. However, you may have additional problems beyond that, and the stack trace will help you identify them.