Develop Reference

Why is there such an arrow in my xml in Android Studio? And how to make it disappear?

Code
<TextView
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_weight="295"
android:background="#drawable/shape_titlebar_background"
android:gravity="center"
android:textColor="#color/color_white"
android:textSize="#dimen/sp_12"/>
Screenshot
The arrow in the red box
How to make it disappear?
Edit
I used #BharaniK's answer .This was only useful in the current activity XML file .
When I create a new activity,It will not be useful in the new activity XML file.And I will reset it .
How to make it disappear in the whole project when I set it up only once?

The arrow mark that you see is the line separator indicated by IDE, as IDE soft-wrapped the lines. The reason why are you seeing for android:background attribute is because the length of that line is higher and it can't indent in the same way as it did for other attributes.
For a better understanding, play around with length of attribute values and text wrap settings in your IDE.

Goto View -> Active Editor and Unmark Use Soft Wraps

Android 5.0 makes unselected checkboxes invisible when background is white

I have an android app that has been working fine pre-Android 5.0. With the update, I noticed that checkboxes and radiobuttons placed on white backgrounds are not visible if they are not selected. For example, this is what a checkbox looks selected and unselected in jellybean:
As you can see, there is a light gray square when the checkbox is not selected. However, after updating to lollipop, this is what it looks like:
So, as you can see, there is no gray square or anything that suggests there is a checkbox here. The same problem happens with radiobuttons. I really don't want to go trough the pain of creating new drawables just for this simple ting. I have seen that checkboxes within the accessibility menu of android 5 have a nice square, but haven't figured out how to make mine look the same:
I tried creating a new android project and just adding some checkboxes and radio buttons with a white background, but they are still invisible when unchecked. I'm using xamarin studio and c#, if that makes any difference. Anyway, I'll understand any java code you post.
This is what my checkbox code looks like:
<CheckBox
android:layout_width="wrap_content"
android:layout_height="0dp"
android:id="#+id/chkSeleccionar"
android:layout_gravity="right"
android:gravity="center_vertical"
android:clickable="false"
android:focusable="false"
android:scaleX="1.5"
android:scaleY="1.3"
android:layout_weight="50"
/>

I couldn't get the theme working, but what did work for me was the following:
android:button="#drawable/abc_btn_check_material"
android:buttonTint="#color/red"
Put this into your CheckBox XML layout.

Just change the
android:buttonTint="YOUR COLOR"
It works.

Make sure you are using a Material theme for Android 5.0 devices - this will ensure you're styling remains consistent with other components. Look for an android:theme element in your AndroidManifest.xml file (either on your application or on an individual activity), then look up what style is set there and check the parent attribute for the style.

Add this attribute
android:buttonTint="#EEEEEE"

Making EditText in android 2.3 to look like as in android higher versions

I am developing an android app in version 2.3. I need to create a editTex that has the same effect as the EditText coast "from" image
![two muppets][1]

You can try it like below.
<EditText
android:id="#+id/editText1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:minLines="5"
android:drawableTop="#drawable/profile_one"
android:ems="10"
android:hint="Tap to enter title"
android:gravity="top|left" >
<requestFocus />
</EditText>
This line android:drawableTop="#drawable/profile_one" will set the image in your edit-text so just replace profile_one this name with your image name.
Like wise you can set image to left, right, and bottom also with following property.
android:drawableBottom="#drawable/profile_one"
android:drawableLeft="#drawable/profile_one"
android:drawableRight="#drawable/profile_one"
Output

You can set image as background to EditText

You can do a nine patch if its only an image back-ground.
So Create a nine patch image that looks like the one you want and apply it as a background to your EditText.
android:background="your image";
To me it appears more like a spinner though.

I am not agree with either of any other answers, but you could use HoloEveryWhere to provide a compatibility and make your EditText looks similar in all the versions.

You can use nine patch image for the background image of edittext.
Are you luking for spinner more specifically custom spinner
Try custom spinner and create edit text as a custom view that It is to be inflate an image.
Refer following link: http://www.androidhive.info/2012/04/android-spinner-dropdown-example/

textview doesn't go multiline

Here's my XML layout example of one of my TextViews which show itself correctly in android 4.2 ... I've downgraded a Nexus S to gingerbread 2.3.6 to test out my application and debug it! Right now, each of my TextViews doesn't take any more space than one line, not even wrapping itself at the end of the first line. (On 4.2, the example below was taking 3 lines and was adding "..." at the end if there was some text missing!)
How can I make my textViews compatible with gingerbread? Thank you!
<TextView
android:id="#+id/TV_guideRow_subtitle"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_alignLeft="#+id/TV_guideRow_title"
android:layout_below="#+id/TV_guideRow_title"
android:text="blabla text that could go up to 3 lines"
android:textColor="#3BB9FF"
android:layout_alignParentRight="true"
android:layout_above="#+id/TV_guideRow_more"
android:layout_marginRight="8dp"
android:layout_marginBottom="3dp"
android:ellipsize="end"
android:maxLines="3"/>

You want:
android:inputType="text|textMultiLine"
Also, depending on the parent of that TextView, multiline may not render properly. Try manually setting the height to, say, 100dp and see if that works.

After some more investigation, I've found out that all my related textView problems were related to my custom theme, which was made for android 4.0+ (since Holo was used as the base theme)
I've set the APIs which doesn't have holo to use the "Light" theme and everything is showing up correctly without any further modification.

Meaning of "No label views point to this text field" warning message

What is the meaning of this warning?
No label views point to this text field with an android:labelFor="#
id/# id/editText1" attribute
Note that the double id (#id/#id) is a problem with the error message text and does not reflect the XML content (which is the correct syntax).

The labelFor is an attribute for accessibility options. You assign this to a label so that if, on a form , user clicks a textedit field , android can know what to read (TalkBack) to user.
The id you assigned to it doesn't seem to be a valid one. why there are two #id in the id? Use ids like this: #id/editText1

I've had the same warning message. It disappeared, when I added a hint to my EditText
android:hint="Some explanation about the input..."

Although I am not familiar with the exact error you have posted. But it definitely sounds like you have done something wrong with the id in the textView. Use id like following in your textView.
android:id="#+id/editText1"
And if you want to set labelFor then use :
android:labelFor="#+id/editText1"

It means that you probably should define a label for this edit text and link them using a labelFor inside that labels definition.
example code:
<TextView
android:id="#+id/my_textView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:labelFor="#+id/my_editText" <!--the plus sign goes first in the code-->
android:text="I'm a label" />
<EditText
android:id="#id/my_editText" <!--no plus sign if not the first-->
android:layout_width="wrap_content"
android:inputType="text"
android:layout_height="wrap_content" />
and it's not only for text views.

Remove th first '#id/' , use like
android:id="#+id/editText1"
which is the correct format. Keep going.. Best wishes.. :)

I solved it by writing both attributes:
android:id="#+id/editText1"
android:labelFor="#+id/editText1"

Select the editText, go to Properties, then Label for and enter #id/EditText1

If the XML looks correct and you're in a Graphical Layout mode then it's probably using a later version of the Android rendering layout that doesn't support EditText.
In Eclipse and Android Studio there should be a green Android icon with what API version is rendering the layout. Make sure you're using a non W or Wearable API as Android W APIs don't support the EditText element. (EditText is most likely not supported because virtual keyboard space is limited on those devices).
The rendered preview should support EditText in any API 4.X version without a trailing W.