Develop Reference

How to fade between ImageViews in an Android app?

I know how to do this for 2 images but what about 3 images.
public void fadeBardock(View view) {
ImageView bardock = (ImageView) findViewById(R.id.bardock);
ImageView goku = (ImageView) findViewById(R.id.goku);
ImageView gohan = (ImageView) findViewById(R.id.gohan);
bardock.animate().alpha(0 f).setDuration(3000);
goku.animate().alpha(0 f).setDuration(4000);
gohan.animate().alpha(1 f).setDuration(5000);
}
After clicking on button I'm directly getting the third image without getting the second image.

Try this code:
bardock.animate().alpha(0f).setDuration(3000);
goku.setAlpha(0f);
goku.animate().alpha(1f).setDuration(3000).setStartDelay(1500);
goku.animate().alpha(0f).setDuration(3000).setStartDelay(4500);
gohan.setAlpha(0f);
gohan.animate().alpha(1f).setDuration(3000).setStartDelay(6000);
You can change duration and start delays to achieve your optimal result.

On More than one imageviews,
1. Create an array of ImageView.
2. Initialize the views in it.
3. assign unique id's to each view in same loop.
[ Another thing is, you can initialize the views in one for loop in onCreate() and then on button click, apply another for loop for animation.]
Now, using an index of array, assign an animation to each view with delay from previous views.
Start animation after the loop and check.
Hope it helps.

How to link many TextViews with their resources

I would like to connect many TextViews with resources, for example, I have got 21 TextViews in xml file which all create a table. I would like to simple attach them to my code, but I want to avoid 21 lines of code.. I thought about looping it, but I am probably wrong, because it doesn't work.
for (int id = 1; id < 21; id++)
textView[id] = (TextView) findViewById(R.id.textView+"id");
}

You can link ViewGroup which is your table here and iterate their childs.
Lets assume we have a linear layout named as mLinearLayout.
for(i=0; mLinearLayout.getChilds.size; i++){
View child = mLinearLayout.getChildAt(i);
if(child instanceof TextView)
mList.add((TextView) child)
}
For more complex layouts you might need recursive functions to iterate child view groups.
Good luck

Instead of findViewById you can try findViewWithTag because now you can use a string argument like what you want.
Of course, you'll probably have to adjust a few things to be able to use this.
Your TextViews will need to be a direct child of a parent layout in your xml and tag them: android:tag="mytext1"
Then in Java, for example:
LinearLayout parentLayout = (LinearLayout) findViewById(R.id.parent);
...
textview[i] = (TextView) parentLayout.findViewWithTag("mytext" + i);
And you can loop that findViewWithTag

Dynamic variables in a for loop?

I've got a layout which is called activity_main.xml which is my parent layout, and I am then inserting a child layout (activity_main_card.xml) within a for loop.
I also have an array, and what I am doing is using the length of the array to determine how many child elements it should create. All of my data to be used in the child element is stored in the array, so the idea is to loop through the array, create a child element for each loop and populate the data.
Instead, what is currently happening is that it is generating the 3 (length of array) child elements, but it is only populating the first one with the latest content in the array. This is because it keeps the variables the same.
What I need to do is somehow set dynamic variables that change as the loop iterates.
The code for my method is as follows:
for (int i = 0; i < cardArray.length; i++) {
LinearLayout item = (LinearLayout)findViewById(R.id.card_holder);
View child = getLayoutInflater().inflate(R.layout.activity_main_card, item, false);
item.addView(child);
//Set objects from array to variables
String cardTitle = cardArray[i][0];
String cardContent = cardArray[i][1];
String cardImage = cardArray[i][2];
//Set XML elements to variables
TextView title = (TextView) findViewById(R.id.card_title);
TextView content = (TextView) findViewById(R.id.card_content);
ImageView image = (ImageView) findViewById(R.id.card_image);
//Load variable content into card layout
title.setText(cardTitle);
content.setText(cardContent);
image.setImageDrawable(getResources().getDrawable(getResources().getIdentifier("drawable/" + cardImage, "drawable", getPackageName())));
}
What I thought I could do was to set the views like:
TextView title[i] = (TextView) findViewById(R.id.card_title);
however this doesn't work. Does anyone know how I can acheive this?

You need to get a reference to the current View you just created and then populate the TextView elements on that View. This is achievable by doing this:
TextView title = (TextView) child.findViewById(R.id.card_title);
TextView content = (TextView) child.findViewById(R.id.card_content);
ImageView image = (ImageView) child.findViewById(R.id.card_image);
You might be better off approaching this problem differently however, as Jonathan suggests a ListView and adapter might suit better for this situation.

You aren't using the View created, you are using the root layout of the activity in every loop because you apply the findViewById in the parent view:
Change:
TextView title = (TextView) findViewById(R.id.card_title);
By;
TextView title = (TextView) child.findViewById(R.id.card_title);

Android - textviews are not visible when dynamically created

I am trying to make an app that lets the user store and saves contacts. It can save, but it has problems listing.
I have a for loop that runs through the database and prints a set of data for each contact (each row), an image (actually its a string because it passes the path) and a string. It prints them in a scrollview with a linear layout for each contact (each contact has a linear layout of its own, so that i can let one contact occupy a row each). The images come out, however, the textviews are nowhere to be found.
Using log.d(textview.getText()); it confirms that the textviews are created and take up space.
http://chesnutcase.heliohost.org/derpbox/itv1.png
Two "contacts" with names, not printed out. The space inbetween is presumbly by the textview.
http://chesnutcase.heliohost.org/derpbox/itv2.png
Another two "contacts", but without names. The dont have a space between each other. Or at least, a significantly smaller space.
Code:
DatabaseHandler db = new DatabaseHandler(this);
int a = (int) (long) db.countRows();
LinearLayout theLayout = (LinearLayout)findViewById(R.id.contactsList);
for(int i = 0;i<a;i++){
ImageButton image = new ImageButton(this);
int density=getResources().getDisplayMetrics().densityDpi;
LinearLayout.LayoutParams vp = new LinearLayout.LayoutParams(density,density, 0.5f);
image.setLayoutParams(vp);
image.setScaleType(ImageView.ScaleType.FIT_END);
int b = a - i;
try {
image.setImageBitmap(decodeUri(Uri.parse(db.getContactData("photo_path")[i])));
} catch (FileNotFoundException e) {
e.printStackTrace();
}
theLayout.addView(image);
TextView tv = new TextView(this);
tv.setText(db.getContactData("name")[i]);
Log.d("UserLog","name is " + db.getContactData("name")[i]);
Log.d("UserLog","textfield contains " + tv.getText());
LinearLayout.LayoutParams vp2 = new LinearLayout.LayoutParams(0,0,1f);
tv.setLayoutParams(vp2);
tv.setBackgroundColor(Color.RED);
theLayout.addView(tv);
}
Any solutions? Thanks in advance

Double check which orientation you've applied to the LinearLayout of your contacts list.
You are setting bad LayoutParams to your TextView. You're making your TextView 0px by 0px with a weight of 1.
LinearLayout.LayoutParams vp2 = new LinearLayout.LayoutParams(0,0,1f);
tv.setLayoutParams(vp2);
Try using one of the MATCH_PARENT or WRAP_CONTENT constants. They're listed here: http://developer.android.com/reference/android/view/ViewGroup.LayoutParams.html#MATCH_PARENT
If you want your TextView to take up the remaining width of the screen I would leave the weight as 1, the width as 0, but you need to set the height to a constant like WRAP_CONTENT.
You're also setting the size of your ImageView to the device screen density (which is a constant) instead of setting a scaling size based off your screen density.

You probably need to call requestLayout(); in order to update the current view layout.
theLayout.requestLayout();
Also it seems you are creating a view with 0 width and 0 height with that layout params:
LinearLayout.LayoutParams vp2 = new LinearLayout.LayoutParams(0,0,1f);

It is better to use ListView for such list.
You will need to write only one Adapter, that's represent logic for creating one row on list.

I would recommend using a CursorAdapter and a layout xml file, this way you can design it to look exactly how you want, and preview it. It is a lot easier than setting all those fiddly LayoutParams
If you have to create them dynamically you may find the text colour is the same as the background, try setting it to something visible like bright red for testing. If you still don't see the text it may be that it's visibility isn't set to View.VISIBLE finally the layout may not be the correct size, a handy tip for this is set the background to a suitably eye catching colour, even if there is no text you should see a shaded block.

Clone textview to append it to a ViewGroup

I have a ViewGroup defined in XML with a view inside, at onCreate time I'd like to have a variable of those.
I don't want to go through the hassle of using a listview+adapter cause its clearly overkill as I know the list won't change since onCreate()
This is more or less the code I'd like to have.
TextView mytextview = myViewGroup.findViewById(R.id.mytext);
for(String test : strings){
mytextview = mytextview.clone();
mytextview.setText(test);
myViewGroup.addView(mytextview);
}
But it is not working.

Maybe use an inflater, and put the textview in an external layout file:
View v = LayoutInflater.from(this).inflate(R.layout.textview_include, null);
viewGroup.addView(v);

Using code of Mathias Lin and using the hint from javahead76:
LinearLayout x = (LinearLayout) findViewById(R.id.container);
for (int i = 0; i < 5; i++) {
View c = LayoutInflater.from(this).inflate(R.layout.singlerow, x);
TextView t = ((TextView)findViewById(R.id.textView1));
t.setId(i+10000);
t.setText("text"+i);
}
TextView b = (TextView) findViewById(10003);
b.setText("10003");

If you do this, you will most likely get the exact same id for every view created this way. This means doing things like ((TextView)v).setText("some text"); will be called on every TextView previously inflated from the same layout. You can still do it this way, but you should call setId() and have some reasonable method for ensuring you do not get the same id twice in a row - incrementation or universal time, etc.
Also, I think Android reserves a certain range of id's for dynamically created id's. You might avoid ID's in this range; but honestly, I don't know the id system works so I could be wrong on this point.