定义构造函数File（Uri）？

Question

i made a wallpaper set application, on my device (Nexus 5) it works great but on Galaxy TAB, Fame or even on Optimus it gives java.lang.OutOfMemory error. someone told me to implement public Bitmap decodeAndResizeFile(File f) but i get

here is my MainActivity code package app.technozed.cablewallpapershd;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;

import android.net.Uri;
 import android.os.Bundle;
 import android.app.Activity;
 import android.app.WallpaperManager;
import android.graphics.Bitmap;
import android.graphics.BitmapFactory;
import android.view.Menu;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Button;
import android.widget.ImageView;
 import android.widget.Toast;

public class MainActivity extends Activity implements OnClickListener {

ImageView display;
int toPhone;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    System.gc();
    toPhone = R.drawable.wal1;
    display = (ImageView) findViewById(R.id.WPdisplay);
    ImageView image1 = (ImageView) findViewById(R.id.WPimg1);
    ImageView image2 = (ImageView) findViewById(R.id.WPimg2);
    ImageView image3 = (ImageView) findViewById(R.id.WPimg3);
    ImageView image4 = (ImageView) findViewById(R.id.WPimg4);
    ImageView image5 = (ImageView) findViewById(R.id.WPimg5);
    ImageView image6 = (ImageView) findViewById(R.id.WPimg6);
    ImageView image7 = (ImageView) findViewById(R.id.WPimg7);
    ImageView image8 = (ImageView) findViewById(R.id.WPimg8);
    ImageView image9 = (ImageView) findViewById(R.id.WPimg9);
    ImageView image10 = (ImageView) findViewById(R.id.WPimg10);
    Button setWall = (Button) findViewById(R.id.BsetWall);
    image1.setOnClickListener(this);
    image2.setOnClickListener(this);
    image3.setOnClickListener(this);
    image4.setOnClickListener(this);
    image5.setOnClickListener(this);
    image6.setOnClickListener(this);
    image7.setOnClickListener(this);
    image8.setOnClickListener(this);
    image9.setOnClickListener(this);
    image10.setOnClickListener(this);       setWall.setOnClickListener(this);
    }

@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;
}

here i implemented it:

public Bitmap decodeAndResizeFile(File f) {

    try {
        // Decode image size
        BitmapFactory.Options o = new BitmapFactory.Options();
        o.inJustDecodeBounds = true;
        BitmapFactory.decodeStream(new FileInputStream(f), null, o);

        // The new size we want to scale to
        final int REQUIRED_SIZE = 70;

        // Find the correct scale value. It should be the power of 2.
        int width_tmp = o.outWidth, height_tmp = o.outHeight;
        int scale = 1;
        while (true) {
            if (width_tmp / 2 < REQUIRED_SIZE
                    || height_tmp / 2 < REQUIRED_SIZE)
                break;
            width_tmp /= 2;
            height_tmp /= 2;
            scale *= 2;
        }
        BitmapFactory.Options o2 = new BitmapFactory.Options();
        o2.inSampleSize = scale;
        return BitmapFactory.decodeStream(new FileInputStream(f), null, o2);
    } catch (FileNotFoundException e) {
    }
    return null;
}

@Override
public void onClick(View v) {
    switch (v.getId()){
    case R.id.WPimg1:
         display.setImageResource(R.drawable.wal1);
         toPhone = R.drawable.wal1;

here i retrive it:

File file=new File(Uri.parse(String.valueOf(toPhone)));

on the line above i get The constructor File(Uri) is undefined error

Bitmap bmpp = decodeAndResizeFile(file);
display.setImageBitmap(bmpp);

         break;
    case R.id.WPimg2:
         display.setImageResource(R.drawable.wal2);
         toPhone = R.drawable.wal2;
         break;
    case R.id.WPimg3:
         display.setImageResource(R.drawable.wal3);
         toPhone = R.drawable.wal3;
         break;
    case R.id.WPimg4:
         display.setImageResource(R.drawable.wal4);
         toPhone = R.drawable.wal4;
         break;
    case R.id.WPimg5:
         display.setImageResource(R.drawable.wal5);
         toPhone = R.drawable.wal5;
         break;
    case R.id.WPimg6:
         display.setImageResource(R.drawable.wal6);
         toPhone = R.drawable.wal6;
         break;
    case R.id.WPimg7:
         display.setImageResource(R.drawable.wal7);
         toPhone = R.drawable.wal7;
         break;
    case R.id.WPimg8:
         display.setImageResource(R.drawable.wal8);
         toPhone = R.drawable.wal8;
         break;
    case R.id.WPimg9:
         display.setImageResource(R.drawable.wal9);
         toPhone = R.drawable.wal9;
         break;
    case R.id.WPimg10:
         display.setImageResource(R.drawable.wal10);
         toPhone = R.drawable.wal10;
         break;
    case R.id.BsetWall:
         try{
               WallpaperManager.getInstance(getApplicationContext()).setResource(toPhone);
             Toast.makeText(getApplicationContext(), "Wallpaper was set!", Toast.LENGTH_SHORT).show();
         } catch(IOException e) {
             e.printStackTrace();
             Toast.makeText(getApplicationContext(), "No privileges!", Toast.LENGTH_SHORT).show();
         }
         break;
    }
    }
    }

how can i define it? what i'm doing wrong?

Answer 1

The file class takes a java.net.URI in its constructor, you're trying to give it an android.net.Uri.

That's what's wrong as far as I can see.

The File class you're using: http://docs.oracle.com/javase/7/docs/api/java/io/File.html

Takes this URI class: http://docs.oracle.com/javase/7/docs/api/java/net/URI.html

You're passing this: http://developer.android.com/reference/java/net/URI.html

Answer 2

I had encountered this error so many times... Finally I came out with one common method to set the image view... Following is the code fragment...

public static void setImageView(ImageView imageView, String path) {
        Log.i("Atul Dravid", path);
        if (path.startsWith("Photo") || path.startsWith("null"))
            return;
        path = path.startsWith("/") ? path : path.substring(6);
        Bitmap picture = (Bitmap) BitmapFactory.decodeFile(path);
        ByteArrayOutputStream stream = new ByteArrayOutputStream();
        picture = Bitmap.createScaledBitmap(picture, 200, 200, false);
        picture.compress(Bitmap.CompressFormat.JPEG, 20, stream);
        byte[] bitmapArray = stream.toByteArray();
        picture = (Bitmap) BitmapFactory.decodeByteArray(bitmapArray, 0, bitmapArray.length);
        //imageView.setImageURI(fileUri);
        imageView.setImageBitmap(picture);
        imageView.setContentDescription(path);


    }

You may want to modify above code for your requirement of resolution of the picture.

Hope this helps.

EDIT

Technically only difference is that I also added Scaling in my code... Try introducing that in your code fragment... I have not found any noticeable degradation in quality of the picture...

Answer 3

Your compile error is because there is no constructor for the class 'File' that takes a Uri object as a parameter. To construct a File object using an Uri, you would do usually call getPath() on the URI to return its path as a String:

File file=new File(Uri.parse(String.valueOf(toPhone)).getPath());

However that will still not solve your problem because 'toPhone' is an integer representing the id of a resource in your project (in this case a drawable). You cannot generate a URI or file path from a resource id in that manner. However in this case, you can work directly with the resource id instead of a file anyway.

Change your decode method to accept a resource identifier (ie an integer):

public Bitmap decodeAndResizeFile(int resID) {

...and use the decodeResource method of BitmapFactory instead of decodeStream (using your Activity's context):

Bitmap bmp= BitmapFactory.decodeResource(context.getResources(), resID, o);

Then you can call it with:

Bitmap bmpp = decodeAndResizeFile(toPhone);

Easiest way to get the context is to declare it as a variable in your Activity class:

private Context context;

...and set it in onCreate():

context = this;

You can then use it wherever you need to in your activity.