In Android, how to create EditText of fixed width?

问题:

I would like to create an EditText which accepts only numbers, has a maximum of 4 numbers, and is never narrower than it would be if filled with 4 numbers (does not shrink when empty, or have to expand to accommodate 4 numbers, so it's fixed.)

The first 2 are accomplished with: android:inputType="number" and android:maxLength="4".

How can I set the minimum length?

回答1:

A little hackish, but you can put your EditText inside a FrameLayout alongside with another TextView with text="0000" and visibility=invisible.

FrameLayout Should have width=wrap_content and your EditText will have width=match_parent.
That should make it the right width always.

The advantage of this is, it's 100% xml-side, no code involved.

<FrameLayout
 android:layout_width="wrap_content"
 android:layout_height="wrap_content">

<TextView
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:text="0000"
    android:visibility="invisible" />

<EditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:inputType="number"
    android:maxLength="4" />
</FrameLayout>

回答2:

One rarely-used (AFAIK) attribute of an EditText that you can use is:

android:ems="4"

This makes the EditText exactly 4 ems wide. An em width is the width of the widest (M) character in the selected font.

回答3:

In my situation, I needed the view to be 6 digits wide. android:ems made the field too wide (since the M-character is wider than a digit).

I ended up using a transparent hint which dictates the minimum width of the field. The example below is six digits wide.

<EditText
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:hint="000000"
        android:textColorHint="#00FFFFFF"
        android:maxLength="6"
        android:inputType="numberPassword" />

This solution is independent of font, letter spacing and other things which may vary. The textColorHint is a 0% opaque white color, so the hint should never be visible to the user.

回答4:

You can also try using. . .

android:ems="4"
android:maxEms="4"
android:layout_width="wrap_content"

. . . this should insure the tightest fit possibly allowed by the default android edittext style

For additional control with the padding on both left and right you can use

android:background="#ffffff"
android:paddingLeft="0dp"
android:paddingRight="0dp"

回答5:

Use android:width="XXX.Xdp"

This lets you set the width in density pixels which ought to be relative to the screen density. I tried using ems based for a field 2 chars wide, but since ems requires a int, 2 was too small and 3 was too big. Blech.

回答6:

There is an incredibly easy way to do this programmatically.

myEditText.setLayoutParams(new LinearLayout.LayoutParams(200, 50));

This would set the width to 200 and the height to 50!!

Enjoy :)

回答7:

Don't know about built-in solution but you can try passivly check the length and rise a dialog with error message at the moment of submission.

回答8:

The problem is, that an EditText widget can loss focus because of a lot of different actions like touching another sensitive view, menu button or (hard keyboard cursor control) and so on. The restiction of a maximum length or type of the input can be done during the tying process (accept the character if it passes the filter or the length is not exceeded). but focus lost can be occour every time - even the submission is not completed yet and the input to short -> therefore there is no build-in minimum length solution, because the application would block at this point the execution of another event or task. At least you have to validate your input before going to the next step in your workflow.

回答9:

I use android:layout_width="60dip" so agree with mike fratto.

The ems solution appears to be interesting as well.

Phil

回答10:

You can set alignment other wise when you put character more than wditText width than It's increase width or EditText width. Please set toLeftOf and toRightOf of the above view to manage this things. Only one solution