问题
In my Android studio project I have a fragment with constraint layout inside. Here is XML.
<android.support.constraint.ConstraintLayout
android:id="@+id/pinLayout"
android:layout_width="match_parent"
android:layout_height="250dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/topLayout">
<android.support.constraint.ConstraintLayout
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/constraintLayout"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:visibility="visible">
<TextView
android:id="@+id/numberTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:gravity="top"
android:text="00000000"
android:textColor="@color/appTintColor"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
<android.support.constraint.ConstraintLayout
android:id="@+id/constraintLayout2"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.4"
app:layout_constraintStart_toStartOf="parent">
<Button
android:id="@+id/confirmButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/rounded_corner_shape_tint"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:text="Confirm Pin"
android:textColor="@color/appMainColor"
android:textSize="14sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
<android.support.constraint.ConstraintLayout
android:id="@+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/constraintLayout2"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.4"
app:layout_constraintStart_toStartOf="parent">
<LinearLayout
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:id="@+id/pinView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
<TextView
android:id="@+id/pinView2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
<TextView
android:id="@+id/pinView3"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
<TextView
android:id="@+id/pinView4"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
</LinearLayout>
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
As you can see the confirm button is centered with constraints in his parent.
But when I am running application in my Xperia z5 compact, a layout inspector shows that button is not centered.
Why does it happen and how to fix that?
Note if I am removing numberTextView with it's parent constarintLayout, the problem disappears. Note In my code I am programmatically setting a text to numberTextView. In case when I am commenting that code i.e not setting text programmatically, button draws correctly.
回答1:
app:layout_constraintHorizontal_bias="0.5"
layout_constraintHorizontal_bias this will make a small variation from center. try code given below,
<Button
android:id="@+id/confirmButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/rounded_corner_shape_tint"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:text="Confirm Pin"
android:textColor="@color/appMainColor"
android:textSize="14sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
回答2:
Remove the below line from your button layout in xml.
app:layout_constraintHorizontal_bias="0.5"
Horizontal Bias: This allows us to position a view along the horizontal axis using a bias value, this will be relative to it’s constrained position.
For more information about Constraint Layout refer this article
回答3:
android:id="@+id/pinLayout" has hight of 250dp that's why button doesn't position at vertically center. try the code given below.
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent">
<android.support.constraint.ConstraintLayout
android:id="@+id/pinLayout"
android:layout_width="match_parent"
android:layout_height="250dp">
<android.support.constraint.ConstraintLayout
android:id="@+id/cl_root"
android:layout_width="match_parent"
android:layout_height="wrap_content"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
tools:visibility="visible">
<TextView
android:id="@+id/numberTextView"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="8dp"
android:gravity="top"
android:text="00000000"
android:textColor="@color/appTintColor"
android:textSize="18sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
<android.support.constraint.ConstraintLayout
android:id="@+id/constraintLayout"
android:layout_width="match_parent"
android:layout_height="0dp"
app:layout_constraintTop_toBottomOf="@id/cl_root"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.4"
app:layout_constraintStart_toStartOf="parent">
<LinearLayout
android:layout_width="0dp"
android:layout_height="0dp"
android:orientation="horizontal"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent">
<TextView
android:id="@+id/pinView1"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
<TextView
android:id="@+id/pinView2"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
<TextView
android:id="@+id/pinView3"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
<TextView
android:id="@+id/pinView4"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:layout_weight="0.25"
android:gravity="center"
android:text="-"
android:textColor="@color/appTintColor"
android:textSize="36sp" />
</LinearLayout>
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
<android.support.constraint.ConstraintLayout
android:id="@+id/constraintLayout2"
android:layout_width="match_parent"
android:layout_height="match_parent"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHeight_percent="0.4"
app:layout_constraintStart_toStartOf="parent">
<Button
android:id="@+id/confirmButton"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:background="@drawable/rounded_corner_shape_tint"
android:paddingLeft="16dp"
android:paddingRight="16dp"
android:text="Confirm Pin"
android:textColor="@color/appMainColor"
android:textSize="14sp"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent" />
</android.support.constraint.ConstraintLayout>
</android.support.constraint.ConstraintLayout>
回答4:
try to use RelativeLayout instead of ConstraintLayout by changing all ConstraintLayout to RelativeLayout in your xml
<android.support.constraint.ConstraintLayout >
...
Your content
...
</android.support.constraint.ConstraintLayout>
to
<RelativeLayout >
...
Your content
...
</RelativeLayout>
then you might give set your button to be center in parent
android:layout_centerInParent="true"
for your TextView pinView1, pinView2, pinView3 and pinView4 you have simply put it inside a LinearLayout.
来源：https://stackoverflow.com/questions/56931441/android-studio-doesnt-draw-button-correctly