Develop Reference

Start a activity like a "Dialog", by writing java code

I want to make a activity like a "Dialog", and I know two ways so far:
Way 1) In Android ApiDemos, it is implemented by adding the attribute to the activity like
android:theme="#android:style/Theme.Dialog">
The result is: the new Activity appears on top of the existing activity, that is what I want.
Way 2) I try to invoke setTheme(android.R.style.Theme_Dialog) in the Activity.onCreate(Bundle) method, and the new activity also appears, but the background is all black. This is not what I want. Code is as below:
super.onCreate(savedInstanceState);
setTheme(android.R.style.Theme_Dialog);
requestWindowFeature(Window.FEATURE_NO_TITLE);
setContentView(R.layout.selecte_date);
Can anybody tell me how to implement the effect by writing Java code?

The easiest way is to add a second layout in you xml which is a overlay of existing one.
then you can set the overlay to visible in your activity. So then you got multiple views in 1 activity.
<?xml version="1.0" encoding="utf-8"?>
<RelativeLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#android:color/transparent" >
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_alignParentTop="true"
android:background="#android:color/transparent">
<ImageView
android:id="#+id/icon"
android:layout_width="fill_parent"
android:layout_height="wrap_content"/>
<TextView
android:id="#+id/title"
android:layout_width="fill_parent"
android:layout_height="fill_parent" />
</LinearLayout>
<LinearLayout
android:layout_alignParentTop="true"
android:id="#+id/overlay"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:background="#color/translucent_black"
android:visibility="false" >
</LinearLayout>
</RelativeLayout>

Accessing Android views on nested layouts

I have trouble accessing Views from a layout that is included in another layout.
Please take a look at this picture:
http://dl.dropbox.com/u/3473245/layout_includes.png
How do I access the 4 text views programmatically?
Its probably something really simple that I'm missing.
Thank you very much!

You can do as follows:
main.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:orientation="vertical" >
<include android:id="#+id/item_base_lang" layout="#layout/dictionary_list_item" />
<include android:id="#+id/item_learn_lang" layout="#layout/dictionary_list_item" />
</LinearLayout>
dictionary_list_item.xml
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="wrap_content" >
<TextView
android:id="#+id/dictionary_list_item_text_header"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<TextView
android:id="#+id/dictionary_list_item_text_content"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
</LinearLayout>
To set the text programmatically:
((TextView)findViewById(R.id.item_base_lang).findViewById(R.id.dictionary_list_item_text_header)).setText("item_base_lang_header");
((TextView)findViewById(R.id.item_base_lang).findViewById(R.id.dictionary_list_item_text_content)).setText("item_base_lang_content");
((TextView)findViewById(R.id.item_learn_lang).findViewById(R.id.dictionary_list_item_text_header)).setText("item_learn_lang_header");
((TextView)findViewById(R.id.item_learn_lang).findViewById(R.id.dictionary_list_item_text_content)).setText("item_learn_lang_content");
This Android wiki page shows how to use reusable UI components with XML layouts, but it doesn't show how to access nested reusable components from code.
Although it is fairly straightforward, it might be not so clear for those who are pretty new to Android Views.

The following two lines should help you get the languageHeader of both includes. You can do the same for languageText
findViewByid(R.id.activityBaseLangView).findViewById(R.id.languageHeader)
findViewByid(R.id.activityLearnLangView).findViewById(R.id.languageHeader)

Webview in TabHost = Starting as black screen

I'm trying to use a webview inside a tabhost that has 4 tabs - all linked to the same webview.
This is great except for one problem:
At start up the webview is black.
Clicking tab 2,3 or 4 makes it "come alive".
My quick fix was to use setCurrentTab(1) and then back to 0, but this looks ugly, so I figured I might as well ask for a solution as I cannot find anything online.
How can this be fixed? Below is my XML:
<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_weight="1">
<android.webkit.WebView android:layout_width="fill_parent" android:id="#+id/webview" android:layout_height="fill_parent" android:scrollbars="none"/>
</FrameLayout>
<TabWidget
android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0"
/>
</LinearLayout>
</TabHost>
Update:
Putting the webview outside of the framelayout causes the app to crash at startup with following error:
java.lang.RuntimeException: Could not create tab content because could not find view with id 2131099648
This happens when I in the onCreate method initialize my tabhost like this:
mTabHost = getTabHost();
mTabHost.addTab(mTabHost.newTabSpec("tab_test1").setIndicator("Tab1", getResources().getDrawable(R.drawable.ligenu)).setContent(R.id.webview));
mTabHost.addTab(mTabHost.newTabSpec("tab_test2").setIndicator("Tab2", getResources().getDrawable(R.drawable.mad)).setContent(R.id.webview));
mTabHost.addTab(mTabHost.newTabSpec("tab_test3").setIndicator("Tab3", getResources().getDrawable(R.drawable.godpris)).setContent(R.id.webview));
mTabHost.addTab(mTabHost.newTabSpec("tab_test4").setIndicator("Tab4", getResources().getDrawable(R.drawable.om)).setContent(R.id.webview));

Break through!
I found the answer to my own question in another SO post that I didn't stumble upon in the past:
Why is my TabHost's FrameLayout's only child loaded with visibility = View.GONE?
Simply setting:
tabHost.getCurrentView().setVisibility(View.VISIBLE);
That fix the issue!

I was having similar problem. As suggested, I put tabHost.getCurrentView().setVisibility(View.VISIBLE); to the code, the webview still come out blank. After a few more searches, this answer saved me. It turns out that it's important to set android:layout_height="wrap_content" to the webview.

Android simple app with TabActivity

I am new to Android and I have been trying to reuse the tutorial on the Android developer website about developing a TabActivity App but, unfortunately, it never worked, even when I constructed it the exact same way as it is described…
Using the debugger it seemed the problem came from the main layout.
-> setContentView(R.layout.main); //After this line the app stops.
Here is my main.xml:
<?xml version="1.0" encoding="utf-8"?>
<TabHost
xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent">
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dp">
<TabWidget
android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content" />
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:padding="5dp" />
</LinearLayout>
</TabHost>
If anyone had the same problem, or if someone have some advices they are welcome :)
Tanks a lot!
Randy

The xml you posted is the same as the TabHost example and there is nothing wrong with it.
There must be something in your code.
Please post the code otherwise we can not help you.

iPhone- like tab bar in Android?

In iPhone we can create a view that has a tab bar and make it the root view of the application then use the tab bar to navigate through sub views.
what is the most close approach to this in Android?
Is it to use a Tabbed Control? but this includes using just one activity.
what is the approach to use in Android to create an activity with a navigation control to other activities in a way similar to that of the iPhone?

There's a tutorial for creating a "Tab Layout" on the android dev site:
You can implement your tab content in
one of two ways: use the tabs to swap
Views within the same Activity, or use
the tabs to change between entirely
separate activities
(source: android.com)

Sorry, I really don't know the iPhone, but may a QuickAction Dialog help you??
http://www.londatiga.net/it/how-to-create-quickaction-dialog-in-android/
I imagine a list of some activities in that dialog.
I hope this is close to what you want.

There are a couple of examples around
http://www.anddev.org/code-snippets-for-android-f33/iphone-tabs-for-android-t14678.html
This one is scrollable
http://code.google.com/p/mobyfactory-uiwidgets-android/

<?xml version="1.0" encoding="utf-8"?>
<TabHost xmlns:android="http://schemas.android.com/apk/res/android"
android:id="#android:id/tabhost"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
>
<LinearLayout
android:orientation="vertical"
android:layout_width="fill_parent"
android:layout_height="fill_parent"
android:layout_marginBottom="0dp"
>
<FrameLayout
android:id="#android:id/tabcontent"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="1"
/>
<TabWidget
android:id="#android:id/tabs"
android:layout_width="fill_parent"
android:layout_height="wrap_content"
android:layout_weight="0"
/>
</LinearLayout>
</TabHost>