Tuesday, 27 November 2012

Android: DialogFragment - dialog sizing

If you've played about creating dialogs using the DialogFragment class, you've probably noticed that the layout_width and layout_height parameters you assign in the xml layout file for your dialog are ignored (disrespected!) and the DialogFragment assigns height and width to the dialog however it so wishes!

Because of this problem and because it is highly recommended to create dialogs with the DialogFragment class, what I do now is to specify the layout_width and layout_height parameters in the xml layout file to have value match_parent. And then, more importantly, what I do is to specify the dialog's size (height and width) in my DialogFragment.onStart() method as follows:
 

@Override
public void onStart() {
  super.onStart();

  // safety check
  if (getDialog() == null) {
    return;
  }

  int dialogWidth = ... // specify a value here
  int dialogHeight = ... // specify a value here

  getDialog().getWindow().setLayout(dialogWidth, dialogHeight);

  // ... other stuff you want to do in your onStart() method
}
 

Android: DialogFragment enter and exit animations

Adding enter and exit animations to your DialogFragment's dialog is a three-step process:
  1. define the enter and exit animations;
  2. add your animations to a style;
  3. set the style as your dialog's "window animations".
That's the gist of it. In greater detail, and assuming you want fade in and fade out animations, this is what you need to do.

First, define the animations. Add a fade_in_dialog.xml file to your res/anim folder which has the following xml code...

<?xml version="1.0" encoding="utf-8"?>
<alpha
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:interpolator="@android:anim/accelerate_interpolator"
  android:fromAlpha="0.0"
  android:toAlpha="1.0"
  android:duration="400" />

And a fade_out_dialog.xml file to your res/anim folder which has the following xml code...

<?xml version="1.0" encoding="utf-8"?>
<alpha
  xmlns:android="http://schemas.android.com/apk/res/android"
  android:interpolator="@android:anim/decelerate_interpolator"
  android:fromAlpha="1.0"
  android:toAlpha="0.0"
  android:duration="400" />

Second, add a style to your res/styles.xml file defined as follows:

<style
  name="dialog_animation_fade" >
  <item name="android:windowEnterAnimation">@anim/fade_in_dialog</item>
  <item name="android:windowExitAnimation">@anim/fade_out_dialog</item>
</style>

Third (and final!), add the following code to your DialogFragment.onStart() method:

@Override
public void onStart() {
  super.onStart();

  // safety check
  if (getDialog() == null) {
    return;
  }

  // set the animations to use on showing and hiding the dialog
  getDialog().getWindow().setWindowAnimations(
      R.style.dialog_animation_fade);
  // alternative way of doing it
  //getDialog().getWindow().getAttributes().
  //    windowAnimations = R.style.dialog_animation_fade;

  // ... other stuff you want to do in your onStart() method
}

Done! Your dialogs should now fade in and fade out when shown and dismissed respectively.

Monday, 19 November 2012

Android Debug Bridge: detect Google Nexus 7 tablet

Spent an awful, awful, awful amount of time this morning trying to hook up a Google Nexus 7 tablet to Android Debug Bridge on my computer.

These are the steps I took which you'd think would suffice:
  • Go to Settings in the tablet,
  • Make Developer Options visible by clicking About Tablet seven times,
  • Enable USB Debugging in Developer Options,
  • Select the app to debug in the Select Debug App option of Developer Options,
  • Install the driver onto my computer as per the instructions here: Using Hardware Devices. I tried the driver in the [Android SDK]\extras\google folder of my computer as well as the one available for download from ASUS.
However, on plugging my tablet into the USB port of my computer and entering the command adb devices in the command prompt, the device was still not listed, i.e. not detected by Android Debug Bridge.

After much wild guessing and frantic searching on Stack Overflow, I finally found the solution, as follows:
  • Go to Settings,
  • then Storage,
  • then USB Computer Connection,
  • then select Camera (PTP) instead of Media Device (MTP).
That should do it!