Android :: GetView Always Giving Null ConvertView Parameter In Preference Class UI
Jul 2, 2010
The preference type of UI is used in many Google built-in applications for example Bluetooth , Wifi etc. And the getView of the preference is used to set the image or text to make it visible in the UI screen.
the getView for the pref type UI is defined as below in framework code : ->
CODE:..............................
Where the convertView is not getting recycled and every time whenever the user is scrolling the list up and down, convertVIew comes out to be null.Therefore by logic inflation of the UI also happens all the time in onCreateView().This is a kind of shortcoming in terms of memory utilization , hence in a discussion (MAKE YOUR UI FAST AND EFFICIENT) where Romain Guy has mentioned about the tricks to increase the app performance doesn't hold good for preference type of UI.
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Nov 14, 2010
I have made customAdapter (which extends BaseAdapter). I want to reuse the old views..
So I am checking:
CODE:........................
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Jun 19, 2010
My app crashes with a null pointer exception on the code below. I have an xml preference file under res/xml/defaults.xml
public class Preference extends Activity {
public Preference() {
} public String getPreference(String key)
{ //it still crashes here
SharedPreferences settings = PreferenceManager.getDefaultSharedPreferences(this.getApplicationContext());
String result = settings.getString(key, null); return result;
} }
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Mar 9, 2009
I want to pass a class reference to an activity, and then the activity will construct the view according to the content of the class.
How could I implement this function?
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Apr 19, 2010
I'm building an android application, which has a list view, and in the list view, a click listener, containing an onItemClick method. So I have something like this:
public class myList extends ListActivity {
@Override
public void onCreate(Bundle savedInstanceState) {
getListView().setOnItemClickListener(new OnItemClickListener() {
public void onItemClick(AdapterView<?> parent, View view,
int position, long id) {
/* Do something*/
}
}
}
Normally, this works fine. However, many times I find myself needing too preform an application using the outer class as a context. thusfar, I've used: parent.getContext(); to do this, but I would like to know, is that a bad idea? I can't really call: because it's not really a subclass, just an embedded one. So is there any better way, or is that considered cosure? Also, if it is the right way, what should I do if the embedded method doesn't have a parameter to get the outside class?
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Jun 9, 2010
I'm new in Android development and I have the next question/problem. I'm playing around with the Media Recorder class to record just audio from the microphone. I'm following the steps indicated in the official site:
http://developer.android.com/reference/android/media/MediaRecorder.html
So I have a method that initializes and configure the MediaRecorder object in order to start recording. Here you have the code:
this.mr = new MediaRecorder();
this.mr.setAudioSource(MediaRecorder.AudioSource.MIC);
this.mr.setOutputFormat(MediaRecorder.OutputFormat.THREE_GPP);
this.mr.setAudioEncoder(MediaRecorder.AudioEncoder.AMR_NB);
this.mr.setOutputFile(this.path + this.fileName);
try { this.mr.prepare();
} catch (IllegalStateException e) { Log.d("Syso", e.toString());
e.printStackTrace();
} catch (IOException e) { Log.d("Syso", e.toString());
e.printStackTrace();
}
When I execute this code in the simulator, thanks to logcat, I can see that the method setAudioSource(MediaRecorder.AudioSource.MIC) gives the next error (with the tag audio_ipunt) when it is called:
ERROR/audio_input(34): unsupported parameter: x-pvmf/media-input-node/cap-config-interface;valtype=key_specific_value
ERROR/audio_input(34): VerifyAndSetParameter failed
And then when the method prepare() is called, I get the another error again:
ERROR/PVOMXEncNode(34): PVMFOMXEncNode-Audio_AMRNB::DoPrepare(): Got Component OMX.PV.amrencnb handle
If I start to record by calling the method start(). I get lots of messages saying:
AudioFlinger(34):RecordThread: buffer overflow
Then after stop and release, I can see that a file has been created, but it doesn't seem that it been well recorded. Anyway, if I try this in a real device I can record with no problems, but I CAN'T play what I just recorded. I guess that the key is in these errors that I've mentioned before.
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Jul 30, 2010
How can I create my own Preference class in andorid? with my own layout and own click listener?
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Jul 28, 2010
I am getting an error , when I try to access the shared preference from within class that extends View.
The Error : "The method getSharedPreferences(String, int) is undefined for the type ViewforRed" , where ViewforRed is my class: Here is the sample code...
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Nov 19, 2010
I'm testing some functions with Android, JNI and NDK. I have the following JAVA class:
import android.app.Activity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
public class JNITest extends Activity {
private int contador;
/** Called when the activity is first created. */...........................
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Jul 29, 2009
I hope someone can share some light on a issue I have with using the convertView that is supplied by the BaseAdapter.
The problem is that I have a couple of different listviews in my app. When using the convertView with listviews that only shows one type everything works fine, and I experience a big performance increase. Nice!
However I also have a listview that can show 4 different types of views, and I see that getView is supplied with a convertView that is of the wrong type.
In my BaseAdapter implementation I have added the following:
CODE:...................
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Nov 4, 2010
I've been scouring throug the examples and tutorials but I can't seem to get my head around how to handle recycling within a subclassed SimpleCursorAdapter. I know that for regular ArrayAdapters you can check convertView for null and inflate if null from the xml and if not null, recycle, but I'm having a little trouble visualizing how that works with the from and to arrays within the SimpleCursorAdapter subclass. I tried to figure this out from the The Busy Coders Guide to Android Development by Commonsware but was unsuccessful. If anyone knows of any tips, examples, or tutorials, I would be grateful to see them.
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Sep 1, 2010
I am new to Android development and have been following the tutorials available on the Android website. I am currently on the section of tutorials for Views, specifically the one for Grid Views: Hello, Grid View Tutorial.I am having trouble understanding how views are made through an adapter. I understand that you must override the getView() method in your adapter class and in this method is where you define how your Views are set up. What I don't understand is where does getView() actually get called? Perhaps I've got the wrong kind of mentality here, but in the code below (the Grid View tutorial) I don't see any calls to getView() (or any other things used in the adapter class such as getCount()).
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Aug 20, 2010
I'm watching this video http://www.youtube.com/watch?v=N6YdwzAvwOA and Romain Guy is showing how to make more efficient UI adapter code using the getView() method. Does this apply to CursorAdapters as well? I'm currently using bindView() and newView() for my custom cursor adapters. Should I be using getView instead?
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Mar 8, 2010
I'm trying to change the content of a row in ListView programmatically. In one row there are 3 TextView and a ProgressBar. I want to animate the ProgressBar if the 'result' column of the current row is zero.
After reading some tutorials and docs, I came to the conclusion that LayoutInflater has to be used and getView() - overriden. Maybe I am wrong on this. code...
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Jul 19, 2010
I've made a customAdapter that accepts an ArrayList. The ArrayList contains a title and then a link. code...
I'm wanting to display the title and then have the on click listener to have the link. I'm having trouble however figuring out a way to do this.
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Mar 31, 2009
I definitely have a memory leak problem and i'm trying to figure out there. After 6-10 config changes i'm getting out of memory in regards to BitmapFactory. I'm kind of suspect that this is going on within adapter. I have a listview . ListItems are an thumbnail image ( ImageView ) and TextView for text.
Here is the getView code.
CODE:..................
And get ThumbnailBitmap() is basically BitmapFactory.decodeByteArray ..
Is it possible that i'm leaking drawables ? Heap is not increasing by the way .
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Aug 18, 2010
When I check my logs, when using ListView, I see, that getView() method of a custom adapter is continuously invoked on first 6 elements, even if I scroll to the very end of the list.
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Jul 15, 2010
I have a list and i want to check is the view is returned so i can call loadingAnimation.start() to make a imageview insite listview animate
Let me tell you what i mean.. code...
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May 20, 2010
I have a ListView with custom ArrayAdapter. Each of the row in this ListView has an icon and some text. These icons are downloaded in background,cached and then using a callback, substituted in their respective ImageViews. The logic to get a thumbnail from cache or download is triggered every time getView() runs.
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Sep 23, 2010
My application uses a list of media files on the phone, i.e. images, audio and video. It also allows the user to filter the list via some checkboxes in a menu, so the user can choose to show or hide each type of files. The way I've been doing this is by putting this in the adapter's getView():
// don't show unwanted file types if (cmo.hasType(MediaType.AUDIO_FILE)){
if(!prefs.getBoolean(PREFS_SHOWAUDIO, true)){ return new ViewStub(mContext);;
} }else if(cmo.hasType(MediaType.IMAGE_FILE)){ if(!prefs.getBoolean(PREFS_SHOWIMG, true)){
return new ViewStub(mContext);;
} }else if( cmo.hasType(MediaType.VIDEO_FILE)){ if(!prefs.getBoolean(PREFS_SHOWVIDEO, true)){ return new ViewStub(mContext);; } }
Which is quite effective in the sense that the list doesn't show those elements. However, the ListView still renders a 1px grey line between each View, even if they are ViewStubs, meaning I see a thick gray line whenever a group of consecutive items are filtered away. How can I get rid of those lines? Should I create a new data array, containing only the elements that should show a view?
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Jan 5, 2010
I have a ListView displaying images on every element of the ListView, It works fine... but when I start to scrolling I have realized my image is downloaded again if it is displayed in the screen of my phone device!
How could I stop reloading the images or all the content of the in ListView again?
Or how could I avoid reading the getView() function again If I have already downloaded all its content?
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Mar 19, 2010
How to invoke the getView method in the baseAdapter in Android from another WebService Bean?
The adapter in my code as follows, I extends the base adapter code...
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Jun 28, 2009
If you derive a class from ArrayAdapter for the purpose of customizing the views of listview items, and you vary the background color of those items by doing something like this in getView()...
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Oct 31, 2013
I am having problems when scrolling a ListView. Each item in the ListView shows an image downloaded from internet.Whenever I scroll the ListView, it calls the method getView(int position, View convertView, ViewGroup parent), causing the image to be downloaded again.
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Jul 7, 2010
I'm creating a new class, using eclipse "New Java Class" dialog box. I can write the superclass I want (I can't find using "browse" button), but I can't write or select an interface to implement. I click "add" but ther is nothing to select. What I'm doing wrong?
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Jul 14, 2010
I'm just getting into Android development, and I have a question about communicating between a receiver class and an activity class. I'm very new to JAVA and Android so I hope I don't sound too stupid. I'm developing an application where I intercept an SMS message and then based on various elements of that SMS I might delete it once it's been saved to the inbox. I have a receiver class that intercepts the txt message, and I am also able to delete messages from my inbox with code in the activity class using a button at the moment. The problem I have is communicating between the receiver class and the activity class where the code to delete a message resides. I tried putting that code directly into the receiver class but as I'm sure most of you already know the BroadcastReceiver class doesn't seem to support what I need to delete messages. I've been searching for an answer to this for a while, but haven't been able to find anything. Honestly I'm not sure I know enough about JAVA and Android to even recognize a solution if I saw it.
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Jun 27, 2010
What I want to do, is be able to access the object neoApi inside the Neoseeker class, from its inner class RunningTimer. Now, in my code, you can see what I would think to work, but when I run my application, nothing pops up. Nothing inside my TextView, no Toast, nothing at all. How can I remedy this?
package com.neoseeker.android.app;
import java.util.Timer;
import java.util.TimerTask;
import org.json.JSONObject;
import android.app.Activity;
import android.app.Notification;
import android.app.NotificationManager;
import android.app.PendingIntent;.......................
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Sep 8, 2010
I'm new to Java and android development. In my application I need data which is accessible for a few activities. I've read that a good solution is to use Application class for this. So I use it like this:
public class MyApplication extends Application {
private String str;
public String getStr(){
return str;
}
public void setStr(String s){
str = s;
}
}
and I can access this variable from activity like this:........................................
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Oct 8, 2010
I have just started android. I just want to know that how can i call activity class from other java class. i just want to pass class object to activity class.
public class GsonParser extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
MagazineThread thread=new MagazineThread();
thread.start();
}
public GsonParser(JsonMagazineParser Obj)
{
}
}
and i am just doing like from other class. GsonParser obj=new GsonParser(this);passing obj to activity class.how can i achieve that.
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Nov 4, 2010
How to pass parameter value to web service in Android?
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