Develop Reference

Android - textview doesn't show up

For some reason, my textview Add a base doesn't show up when I launch the app on my phone. I have no idea why, 'cause it is displayed on Android studio :O

Replace tools:text="#string/add_base" with android:text="#string/add_base"
Attributes in the tools namespace are shown only when designing layouts. When you build your app, the build tools remove these attributes so there is no effect on your APK size or runtime behavior.
Reference: https://developer.android.com/studio/write/tool-attributes

tools:text="YOUR TEXT" can be used for your design and preview purpose.
If you add any text as a tools:text app will not use this text as that is not the actual text that should be rendered on the app
So instead of this, you should use android:text="YOUR TEXT"

Ltr for Persian locale in android

I am developing an app which supports two languages: English("en") and Persian("fa"). I have set android:supportsRtl="false" in AndroidManifest.xml since I need everything to be from left to right. I set margins for all views that I have but for the ones containing a string, it is not working right and it still seems like it is setting the directions from right to left. How can I fix that? I also tried changing the layoutDirection manually to left to right but that did not work either.

You must handle your locale in all activities. Android by default uses the locale of the device to select the appropriate language dependent resources.
Also you must consider project minimum sdk. I recommended to you change it to 16 or higher: minSdkVersion 16
Maybe this link help you.
I set margins for all views that I have but for the ones containing a string, it is not working right
For this for example you must use from android:layout_marginEnd instead of android:layout_marginRight. Also in default create your layout for en locale and then handle and change it by app locale to fa or another locale.

You have to use instead of the right from the end and instead of the left from the start
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="تست"
android:gravity="start"/>

Can you set graphical layout preview-only text on a TextView?

I have a styled TextView whose real text is populated dynamically at runtime. The Graphical Layout view is very useful for getting a feel on how this component works with others in terms of look and feel, etc. There is no sensible default to this text field and I wish it to be blank before being populated. If I don't specify any text in the TextView declaration then the TextView is blank. I can set the text manually using:
<TextView
...
android:text="Preview text"/>
and then switch to the Graphical Layout. However, I must remember to remove this or risk it being shipped in my production version.
Is there a way to specify text which is only seen in the Graphical Layout preview but not applicable at runtime?
EDIT: I'm using Eclipse ADT.

Yes you can with the design tools extension attributes in Android Studio.
See this page https://developer.android.com/studio/write/tool-attributes.html
Basically you define the tools namespace
xmlns:tools="http://schemas.android.com/tools"
Then use it to set your placeholder text.
<EditText
tools:text="John Doe"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
This actually works with most (if not all xml attributes).
e.g
tools:visibility="gone"
would set the preview visibility to "gone" but the runtime visibility would be unchanged.

I don't believe there is, the only possible way is when you declare your TextView, you say after, tv.setText(""); this way you will always find it blank at runtime

Android TextView won't show right number of lines in Android 2.3

I have a couple of TextViews in my app, which should have exactly 3 lines. This works on Android 3+, but on Android 2.3, which I'd also like to support, these fields have exactly 2 lines. I've also tried TextView.setLines(3); in code, but that does not seem to help. This is my TextView:
<TextView
d1p1:lines="3"
d1p1:maxLines="3"
d1p1:minLines="3"
d1p1:ellipsize="end"
d1p1:text="Some Text"
d1p1:textAppearance="?android:attr/textAppearanceMedium"
d1p1:layout_width="fill_parent"
d1p1:layout_height="55dp"
d1p1:id="#+id/detailsTextView"
d1p1:layout_below="#+id/locationTextView"
d1p1:textSize="13dp"
d1p1:textColor="#color/app_darkgray"
d1p1:background="#color/app_dark_background"
d1p1:layout_marginLeft="#dimen/sr_horizontal_padding"
d1p1:layout_marginRight="#dimen/sr_horizontal_padding" />
Setting the height to wrap_content also does not work.

After some research it looks like my suspicion is correct. As discussed here (ellipsize multiline textview), Ellipsize causes issues with the min/max lines attributes. Because of this you may want to consider avoiding the Ellipsize otherwise, if that is not an option, you can follow the instructions in the other thread to use a custom TextView class to work around the problem.

How to make the text direction from right to left

I want to write text in (right to left language i.e. Arabic) in a TextView. But I want to make the text writing direction from right to left. gravity:rightwill align the text to right only. I want to justify the text from right to left ( to make the words and numbers appear in he entered order in the line ) . how ?

Another clever way which can be used in older versions of android and can be used anywhere in string so it's handier even in latest version of android, is to include the right-to-left mark or even left-to-right mark in the string when it's needed:
left-to-right mark: ‎ or ‎ (U+200E)
right-to-left mark: ‏ or ‏ (U+200F)
This is how it's down:
String rtl = "Hello \u200F(سلام)";
The good thing about this method is you can even use it after punctuation like (,{,[,! which are positioned right incorrectly! examples:
سلام! // wrong position
سلام!‏ // right position by adding RLM after !
look how ! is positioned correctly in second line, actually there is an RLM after it, and you can copy paste it even if it's invisible.
The second good thing as you saw it is that you can use this method (these char codes) in any system that supports RTL like browsers, word and so on.

Just put this property in your TextView and everything will workout just fine it will automatically detect your text and change accordingly
android:textDirection="anyRtl"

Too late , but the android:gravity="right" worked.

set this line in xml for textview :
android:textDirection="locale"

Try using
textview.setTextDirection(View.TEXT_DIRECTION_RTL);
or
textview.setTextDirection(View.TEXT_DIRECTION_ANY_RTL);

In case of normal edit text this will work
android:textDirection="rtl"
But in case of password fields this is not enough then follow this;
android:textDirection="rtl"
android:gravity="right"

Use android:layoutDirection="rtl" and android:textAlignment="viewStart" to make the text view right-to-left.

try this as it worked for me android:textDirection="rtl"

Add these to your editText:
android:gravity="right"
android:textDirection="rtl"
PS: android:textDirection requires API level 17

just adding my own experience with such issues. in my case in addition to suggested solutions i also had to replace English " character with the RTL (in my case hebrew) representation of such character ״

By using attributes as below in my xml code strangely I got a right to left text with correct punctuation. But this is not a perfect solution for multi language text:
android:textDirection="ltr"
android:gravity="right"
setting ltr corrects punctuation problems like having dot on right side instead of left.
gravity attribute makes text flow from right to left.

best way textDirection for TextView, Don't use layoutDirection
<TextView
android:id="#+id/viewCountTv"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:textDirection="anyRtl"
android:gravity="center"/>