我在 Android Studio 中遇到了布局预览的奇怪行为。我开发了一个扩展 AppCompatButton 的自定义视图，并且布局是运行时的预期布局，但是，布局预览中的布局显示不正确。特别是，显示按钮，但没有从自定义属性设置背景颜色，也没有 drawableStart（根据名为“social”的自定义属性在自定义视图初始化中设置）。有关其他详细信息，请参阅下面的代码。请注意，自定义视图位于作为模块导入主项目的库中。我在这里想念什么？谢谢 ：）
自定义视图代码：
public class SocialButton extends AppCompatButton {
private static final String TAG = SocialButton.class.getSimpleName();
Context mContext;
int backgroundColor;
int socialId;
int textColor;
public SocialButton(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
mContext = context;
TypedArray a = context.getTheme().obtainStyledAttributes(
attrs,
R.styleable.SocialButton,
0, 0);
initDefaults(a);
setIconForSocial();
initStateListDrawable();
}
public void initDefaults(TypedArray a){
try {
backgroundColor = a.getColor(R.styleable.SocialButton_backgroundColor, Color.WHITE);
textColor = a.getColor(R.styleable.SocialButton_textColor,
ContextCompat.getColor(mContext,R.color.social_button_text_color));
socialId = a.getInt(R.styleable.SocialButton_social, 0);
} finally {
a.recycle();
}
}
public void initStateListDrawable(){
StateListDrawable stateListDrawable = new StateListDrawable();
GradientDrawable drawable;
// Pressed, focused
drawable = new GradientDrawable();
drawable.setShape(GradientDrawable.RECTANGLE);
drawable.setColor(ContextCompat.getColor(mContext,R.color.border_button_ripple_color));
stateListDrawable.addState(new int[]{android.R.attr.state_pressed}, drawable);
stateListDrawable.addState(new int[]{android.R.attr.state_focused}, drawable);
// Disabled
drawable = new GradientDrawable();
drawable.setShape(GradientDrawable.RECTANGLE);
drawable.setColor(ContextCompat.getColor(mContext,R.color.raised_disabled_color));
stateListDrawable.addState(new int[]{-android.R.attr.state_enabled}, drawable);
// Normal
drawable = new GradientDrawable();
drawable.setShape(GradientDrawable.RECTANGLE);
drawable.setColor(backgroundColor);
stateListDrawable.addState(new int[]{android.R.attr.state_enabled}, drawable);
setBackground(stateListDrawable);
setTextColor(textColor);
setAllCaps(false);
}
public void setBackgroundColor(int color){
backgroundColor = color;
initStateListDrawable();
}
private void setIconForSocial(){
Drawable img;
if (socialId == 0){
img = getContext().getResources().getDrawable( R.drawable.ic_google );
}else{
img = getContext().getResources().getDrawable( R.drawable.ic_facebook );
}
//setPadding(LayoutUtils.dpToPx(27,mContext),LayoutUtils.dpToPx(27,mContext),
//LayoutUtils.dpToPx(27,mContext),LayoutUtils.dpToPx(27,mContext));
setCompoundDrawablesWithIntrinsicBounds( img, null, null, null);
}
}
布局中的自定义视图 xml：
<?xml version="1.0" encoding="utf-8"?>
<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:background="#F5F5F5"
android:paddingBottom="16dp"
tools:context="it.zehus.bitridesharing.login.SignInActivity">
<com.daimajia.slider.library.SliderLayout
android:id="@+id/slider"
android:layout_width="0dp"
android:layout_height="0dp"
app:layout_constraintBottom_toTopOf="@+id/gd40"
app:layout_constraintDimensionRatio=""
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintVertical_bias="0.0"
tools:background="#800000FF" />
<android.support.constraint.Guideline
android:id="@+id/gd40"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.40" />
<android.support.constraint.Guideline
android:id="@+id/gd63"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:orientation="horizontal"
app:layout_constraintGuide_percent="0.63" />
<com.daimajia.slider.library.Indicators.PagerIndicator
android:id="@+id/custom_indicator"
style="@style/AndroidImageSlider_Magnifier_Oval_Green"
android:layout_width="395dp"
android:layout_height="27dp"
android:layout_alignParentBottom="true"
android:layout_alignParentStart="true"
android:layout_marginTop="16dp"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/tvCaption" />
<com.zehus.customlayouts.buttons.BorderButton
android:id="@+id/btCreateAccount"
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_marginEnd="24dp"
android:layout_marginStart="24dp"
android:layout_marginTop="12dp"
android:text="Create an account"
android:textAllCaps="false"
android:textSize="16sp"
app:borderColor="@color/colorPrimary"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/btFacebookLogin"
app:textColor="@color/colorPrimary" />
<com.zehus.customlayouts.buttons.SocialButton
android:id="@+id/btFacebookLogin"
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_gravity="center_horizontal"
android:layout_marginEnd="24dp"
android:layout_marginStart="24dp"
android:layout_marginTop="12dp"
app:social="Facebook"
android:text="@string/continue_with_facebook"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/btGoogleLogin" />
<com.facebook.login.widget.LoginButton
android:id="@+id/btPhantomFbLogin"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_gravity="center_horizontal"
android:layout_marginTop="30dp"
android:layout_marginBottom="30dp"
android:visibility="gone" />
<com.zehus.customlayouts.buttons.SocialButton
android:id="@+id/btGoogleLogin"
android:layout_width="0dp"
android:layout_height="40dp"
android:layout_marginEnd="24dp"
android:layout_marginStart="24dp"
android:layout_marginTop="8dp"
android:text="@string/continue_with_google"
app:social="Google"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toTopOf="@+id/gd63">
</com.zehus.customlayouts.buttons.SocialButton>
<Button
android:id="@+id/btSignIn"
style="@style/Widget.AppCompat.Button.Borderless"
android:layout_width="0dp"
android:layout_height="wrap_content"
android:layout_marginEnd="24dp"
android:textColor="@color/colorPrimary"
android:layout_marginStart="24dp"
android:text="Sign in"
android:textAllCaps="false"
app:layout_constraintBottom_toBottomOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.5"
app:layout_constraintStart_toStartOf="parent" />
<TextView
android:id="@+id/tvCaption"
android:layout_width="wrap_content"
android:layout_height="21dp"
android:layout_marginTop="16dp"
android:text="Hybrid vs Boost"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintHorizontal_bias="0.498"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintTop_toBottomOf="@+id/slider" />
</android.support.constraint.ConstraintLayout>