我有一个自定义的ConstraintLayout类(Card.java),它覆盖了onDraw()
方法,在他的背景中绘制一个六边形。在前景我试着有三个TextViews
来显示三个数字。为此,我在卡的构造函数中膨胀了一个card.xml
。将显示TextView,但不会显示在正确的位置。它们应与卡的宽度和高度相匹配,然后将其自身定位到卡的左上角和右上角以及一个到底部。但他们做的事情就像收缩自己并转到左上角。
我试图将card.xml的根元素更改为“merge
”而不是“... ConstraintLayout
”,但这并没有改变任何东西。
我还尝试使用指南来定位TextViews相对于它的宽度。我试图阻止使用固定边距,因此Text总是在正确的位置,也就是当卡的大小发生变化时。
card.Java:
public class Card extends ConstraintLayout {
private int mSize;
private Path mHexagon;
private Paint mPaintHexagon;
private TextView mT1, mT2, mT3;
public Card(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
inflate(context, R.layout.card, this);
// Numbers
mT1 = findViewById(R.id.num1);
mT2 = findViewById(R.id.num2);
mT3 = findViewById(R.id.num3);
// Hexagon
mSize = Field.getHexSize(); // Size is used to calculate the
setPath();
mPaintHexagon = new Paint(Paint.ANTI_ALIAS_FLAG);
mPaintHexagon.setColor(0x50888888);
mPaintHexagon.setStyle(Paint.Style.FILL);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
canvas.drawPath(mHexagon, mPaintHexagon);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int width = 2 * mSize;
int height = (int) (Math.sqrt(3) * mSize);
Log.d(TAG, "Measure w:" + width + " h:" + height);
setMeasuredDimension(width, height);
}
}
card.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"
android:layout_width="match_parent"
android:layout_height="match_parent"
>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/num2"
android:textAppearance="@style/TextAppearance.AppCompat.Large"
android:text="2"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="8dp"
app:layout_constraintStart_toStartOf="parent"
android:layout_marginStart="8dp"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/num1"
android:textAppearance="@style/TextAppearance.AppCompat.Large"
android:text="1"
app:layout_constraintStart_toEndOf="@+id/num2"
app:layout_constraintEnd_toStartOf="@+id/num3"
app:layout_constraintBottom_toBottomOf="parent"/>
<TextView
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:id="@+id/num3"
android:textAppearance="@style/TextAppearance.AppCompat.Large"
android:text="3"
app:layout_constraintEnd_toEndOf="parent"
android:layout_marginEnd="8dp"
app:layout_constraintTop_toTopOf="parent"
android:layout_marginTop="8dp"/>
</android.support.constraint.ConstraintLayout>
activity_main.xml中:
<?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"
tools:context=".MainActivity"
android:background="@color/colorAccentDark"
android:padding="5dp">
<de.portugall.markus.takeiteasy.Card
android:layout_width="wrap_content"
android:layout_height="wrap_content"
app:layout_constraintTop_toTopOf="parent"
app:layout_constraintEnd_toEndOf="parent"
app:layout_constraintStart_toStartOf="parent"
app:layout_constraintBottom_toBottomOf="parent"
android:id="@+id/card"/>
</android.support.constraint.ConstraintLayout>
'onMeasure()`有一些你没有严格遵守的rules。我已经看到这些规则被打破而不受惩罚,但我认为你被抓住了,但我们会坚持下去。
在onMeasure()
中,您设置自定义布局的高度和宽度,但ConstraintLayout
仍然将布局理解为wrap_content
。您需要将布局参数设置为新的高度和宽度。将以下代码添加到onMeasure()
的末尾:
// Although we have measured the layout, we need to tell ConstraintLayout in the
// LayoutParams that the size is not longer "wrap_content".
ViewGroup.LayoutParams lp = getLayoutParams();
lp.width = width;
lp.height = height;
setLayoutParams(lp);
您遇到的第二个问题是您将ConstraintLayout
(card.xml)添加到ConstraintLayout
(您的自定义布局),但您没有设置约束。在Card.java
的构造函数中,添加以下内容以设置约束:
ConstraintLayout layout = (ConstraintLayout) inflate(context, R.layout.card, this);
// We have added R.layout.card to a ConstraintLayout (this custom layout), so we need
// to make sure that it is constrained properly.
ConstraintSet cs = new ConstraintSet();
cs.clone(layout);
cs.connect(R.id.layout, ConstraintSet.START, ConstraintSet.PARENT_ID, ConstraintSet.START);
cs.connect(R.id.layout, ConstraintSet.TOP, ConstraintSet.PARENT_ID, ConstraintSet.TOP);
cs.connect(R.id.layout, ConstraintSet.END, ConstraintSet.PARENT_ID, ConstraintSet.END);
cs.connect(R.id.layout, ConstraintSet.BOTTOM, ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM);
cs.applyTo(layout);
您需要将card.xml
中布局的高度和宽度更改为0dp
。 match_parent
永远不适合ConstraintLayout
。
这是对正在发生的事情的图片描述:
在相关的说明中,你应该考虑using the merge facility以避免嵌套的ConstraintLayouts
,正如其他人提到的那样。