I am using WVGA800 skin in Android emulator, so the density (hw.lcd.density) is 240. I have to put 4 image buttons (72 pixels per inch) at the bottom of activities view. As the resolution is 480X800, I asummed that the width of image must be 120 pixels. The problem is when application is launched, the 3 buttons take all width and there is no place for 4th button… Then I created button image in Fireworks with resolution 240 pixels per inch and in 120px width, but problem remains. Could somebody explain how to make correct drawables (sizes and dpi) so that they can be displayed pixel in pixel on Android?
Android, images and dpi
androiddpiresolution
Related Solutions
Here's what I created to hold the images that my app is currently displaying. Please note that the "Log" object in use here is my custom wrapper around the final Log class inside Android.
package com.wilson.android.library;
/*
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements. See the NOTICE file
distributed with this work for additional information
regarding copyright ownership. The ASF licenses this file
to you under the Apache License, Version 2.0 (the
"License"); you may not use this file except in compliance
with the License. You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing,
software distributed under the License is distributed on an
"AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
KIND, either express or implied. See the License for the
specific language governing permissions and limitations
under the License.
*/
import java.io.IOException;
public class DrawableManager {
private final Map<String, Drawable> drawableMap;
public DrawableManager() {
drawableMap = new HashMap<String, Drawable>();
}
public Drawable fetchDrawable(String urlString) {
if (drawableMap.containsKey(urlString)) {
return drawableMap.get(urlString);
}
Log.d(this.getClass().getSimpleName(), "image url:" + urlString);
try {
InputStream is = fetch(urlString);
Drawable drawable = Drawable.createFromStream(is, "src");
if (drawable != null) {
drawableMap.put(urlString, drawable);
Log.d(this.getClass().getSimpleName(), "got a thumbnail drawable: " + drawable.getBounds() + ", "
+ drawable.getIntrinsicHeight() + "," + drawable.getIntrinsicWidth() + ", "
+ drawable.getMinimumHeight() + "," + drawable.getMinimumWidth());
} else {
Log.w(this.getClass().getSimpleName(), "could not get thumbnail");
}
return drawable;
} catch (MalformedURLException e) {
Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
return null;
} catch (IOException e) {
Log.e(this.getClass().getSimpleName(), "fetchDrawable failed", e);
return null;
}
}
public void fetchDrawableOnThread(final String urlString, final ImageView imageView) {
if (drawableMap.containsKey(urlString)) {
imageView.setImageDrawable(drawableMap.get(urlString));
}
final Handler handler = new Handler() {
@Override
public void handleMessage(Message message) {
imageView.setImageDrawable((Drawable) message.obj);
}
};
Thread thread = new Thread() {
@Override
public void run() {
//TODO : set imageView to a "pending" image
Drawable drawable = fetchDrawable(urlString);
Message message = handler.obtainMessage(1, drawable);
handler.sendMessage(message);
}
};
thread.start();
}
private InputStream fetch(String urlString) throws MalformedURLException, IOException {
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpGet request = new HttpGet(urlString);
HttpResponse response = httpClient.execute(request);
return response.getEntity().getContent();
}
}
You can force Android to hide the virtual keyboard using the InputMethodManager, calling hideSoftInputFromWindow
, passing in the token of the window containing your focused view.
// Check if no view has focus:
View view = this.getCurrentFocus();
if (view != null) {
InputMethodManager imm = (InputMethodManager)getSystemService(Context.INPUT_METHOD_SERVICE);
imm.hideSoftInputFromWindow(view.getWindowToken(), 0);
}
This will force the keyboard to be hidden in all situations. In some cases, you will want to pass in InputMethodManager.HIDE_IMPLICIT_ONLY
as the second parameter to ensure you only hide the keyboard when the user didn't explicitly force it to appear (by holding down the menu).
Note: If you want to do this in Kotlin, use:
context?.getSystemService(Context.INPUT_METHOD_SERVICE) as InputMethodManager
Kotlin Syntax
// Only runs if there is a view that is currently focused
this.currentFocus?.let { view ->
val imm = getSystemService(Context.INPUT_METHOD_SERVICE) as? InputMethodManager
imm?.hideSoftInputFromWindow(view.windowToken, 0)
}
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Best Answer
If you put your images in
res/drawable
, Android assumes they're for 160dpi and scales them accordingly for different resolutions.Your options are either to put the button images into
res/drawable-hdpi
signaling that they're intended for densities around 240dpi, or intores/drawable-nodpi
to make them never scale regardless of the current screen density.You still reference them as
@drawable/whatever
in layouts, the engine picks the best match automatically.