问题
With this xml:
<LinearLayout
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="25"
android:text="@string/id"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextID"
android:layout_width="0dp"
android:background="@drawable/greyframe"
android:layout_weight="25"
android:layout_height="wrap_content" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="25"
android:text="@string/pack_size"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextPackSize"
android:background="@drawable/greyframe"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="25" />
</LinearLayout>
...the EditTexts do not even display. Why? This is a followup to my question here, which has grown so long that I can no longer add to it.
UPDATE
Okay, this looks purdy darn purdy ("...HUH?!? I think I look kinda purdy, don't you?!?" <= guess that flick):
<ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="match_parent">
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:paddingBottom="@dimen/activity_vertical_margin"
android:paddingLeft="4dp"
android:paddingRight="@dimen/activity_horizontal_margin"
android:paddingTop="@dimen/activity_vertical_margin"
tools:context="hhs.app.DeliveryActivity">
<!--Row 0-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<Spinner
android:id="@+id/spinnerUPCPLU"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="40"
android:entries="@array/delivery_upcplu_spinner" />
<EditText
android:id="@+id/editTextUPCPLU"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="60"
android:editable="false" />
</LinearLayout>
<!--Row 1-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="7"
android:text="@string/id"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextID"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="34"
android:background="@drawable/greyframe" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="23"
android:text="@string/pack_size"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextPackSize"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="34"
android:background="@drawable/greyframe" />
</LinearLayout>
<!--Row 2-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:text="@string/desc"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextDesc"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="8"
android:background="@drawable/greyframe" />
</LinearLayout>
<!--Row 3-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/qty"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextQty"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="3"
android:background="@drawable/orangeframe" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:text="@string/count"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextCount"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="3"
android:background="@drawable/greyframe"
android:editable="false" />
</LinearLayout>
<!--Row 4-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/cost"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editCost"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/orangeframe" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1.2"
android:text="@string/margin"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextMargin"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/orangeframe" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.6"
android:text="@string/list"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editList"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/orangeframe" />
</LinearLayout>
<!--Row 5-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/dept"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Spinner
android:id="@+id/spinnerDept"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:background="@drawable/greyframe"
android:entries="@array/departments" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="0.4"
android:text="$"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextDollar"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:background="@drawable/greyframe" />
</LinearLayout>
<!--Row 6-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/sub_dept"
android:textAppearance="?android:attr/textAppearanceMedium" />
<Spinner
android:id="@+id/spinnerSubdept"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="5"
android:background="@drawable/greyframe"
android:entries="@array/subdepartments" />
</LinearLayout>
<!--Row 7-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:background="@drawable/box"
android:orientation="vertical">
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/delivery_invoice_number"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextDelivInvNum"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/greyframe"
android:editable="false" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/vendor"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextVendor"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/greyframe"
android:editable="false" />
</LinearLayout>
<!--Row 8-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:text="@string/total_dollars"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextTotalDollars"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/greyframe" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="2"
android:text="@string/current_total"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextCurrentTotal"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/greyframe" />
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/qty"
android:textAppearance="?android:attr/textAppearanceMedium" />
<EditText
android:id="@+id/editTextReadonlyQty"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:background="@drawable/greyframe" />
</LinearLayout>
</LinearLayout>
<!--Row 9-->
<LinearLayout
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp">
<Button
android:id="@+id/buttonSave"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/save" />
<Button
android:id="@+id/buttonFind"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/find" />
<Button
android:id="@+id/buttonClear"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/clear" />
</LinearLayout>
</LinearLayout>
</ScrollView>
UPDATE 2
This is how that layout looks at design-time in Droidio:
It's not Yosemite, but neither is it Tonopah, Nevada.
UPDATE 3
Based on what I read here, I changed the "dp"s to "dip"s.
回答1:
Here I demonstrate you that no, it isn't so.
Just that I used 1 for weights instead of 25, for shortness (1 char saved for 4 Views = 4 chars saved).
Multiply it for 10 rows, 40 chars saved, which is 80 bytes in UTF-8.
Small optimizations...
Try this, B. Clay:
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout
xmlns:android="http://schemas.android.com/apk/res/android"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:orientation="horizontal"
android:padding="5dp"
>
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/id"
android:textAppearance="?android:attr/textAppearanceMedium"
/>
<EditText
android:id="@+id/editTextID"
android:layout_width="0dp"
android:layout_weight="1"
android:layout_height="wrap_content"
/>
<TextView
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
android:text="@string/pack_size"
android:textAppearance="?android:attr/textAppearanceMedium"
/>
<EditText
android:id="@+id/editTextPackSize"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_weight="1"
/>
</LinearLayout>
I got this result:
I just removed the android:background="@drawable/greyframe", since I haven't got that resource.
Note that the trial has been done on an emulated 2.8" ldpi (240*320) screen.
回答2:
I believe the layout width of your LinearLayout container must be definite for weight to recalculate width of child containers. Try changing its width from "wrap_content" to "fill_parent".
回答3:
The width of your views is set to 0dp. Try changing those to "match_parent".
来源：https://stackoverflow.com/questions/23917609/why-do-my-edittexts-not-display-at-all