父级中心不适用于自定义相对布局

时间:2016-11-01 07:03:33

标签: android android-layout relativelayout

我正在尝试创建自定义布局" SquareBox"基于相对布局将ImageView保持在中心。 此自定义布局将始终采用方形大小(取决于ImageView的高度和宽度)。

protected void onMeasure(int width, int height) {
    super.onMeasure(width, height);
    int measuredWidth = getMeasuredWidth();
    int measuredHeight = getMeasuredHeight();
    int size;
    if (measuredWidth > measuredHeight) {
        size = measuredWidth;
    } else {
        size = measuredHeight;
    }
    setMeasuredDimension(size, size);
}

这是我的布局代码:

  <com.example.tools.SquareBox
        android:id="@+id/square_box"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:background="@android:color/darker_gray">

    <ImageView
        android:id="@+id/canvas_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="0dp"
        android:layout_centerInParent="true"
        android:adjustViewBounds="true"
        android:scaleType="fitCenter"
        tools:src="@drawable/demo_image" />
</com.example.tools.SquareBox>

工作正常,但图像视图不在此自定义视图的中心。 我试过以下: - &GT;机器人:layout_centerInParent =&#34;真&#34;对于ImageView。

- &GT;机器人:比重=&#34;中心&#34; for&#34; SquareBox&#34;。

- &gt;以编程方式将CENTER_IN_PARENT添加到SquareBox的onMeasure方法中的ImageView。

但没有任何效果。 我在这里缺少什么?

3 个答案:

答案 0 :(得分:1)

将您的布局更改为此(将layout_width更改为match_parent):

<com.example.tools.SquareBox
        android:id="@+id/square_box"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:gravity="center"
        android:background="@android:color/darker_gray">

    <ImageView
        android:id="@+id/canvas_image"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:layout_margin="0dp"
        android:layout_centerInParent="true"
        android:adjustViewBounds="true"
        android:scaleType="fitCenter"
        tools:src="@drawable/demo_image" />
</com.example.tools.SquareBox>

并将您的自定义布局更改为:

  @Override
  protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    int widthMode = MeasureSpec.getMode(widthMeasureSpec);
    int widthSize = MeasureSpec.getSize(widthMeasureSpec);
    int heightMode = MeasureSpec.getMode(heightMeasureSpec);
    int heightSize = MeasureSpec.getSize(heightMeasureSpec);

    int size;
    if(widthMode == MeasureSpec.EXACTLY && widthSize > 0){
      size = widthSize;
    }
    else if(heightMode == MeasureSpec.EXACTLY && heightSize > 0){
      size = heightSize;
    }
    else{
      size = widthSize < heightSize ? widthSize : heightSize;
    }

    int finalMeasureSpec = MeasureSpec.makeMeasureSpec(size, MeasureSpec.EXACTLY);
    super.onMeasure(finalMeasureSpec, finalMeasureSpec);
  }

答案 1 :(得分:0)

试试这个: - android:layout_gravity="center_horizontal"

答案 2 :(得分:0)

我以另一种方式模仿了方框行为。我认为这是一种解决方法,它可能不是最好的解决方案,但它有效。我想知道更好更清洁的解决方案。

布局文件:

<?xml version="1.0" encoding="utf-8"?>
<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">

    <RelativeLayout
        android:id="@+id/square_box_holder"
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_margin="0dp"
        android:layout_weight="3">

        <View
            android:id="@+id/square_box"
            android:layout_width="0dp"
            android:layout_height="0dp"
            android:layout_centerInParent="true"
            android:background="@android:color/darker_gray" />


        <ImageView
            android:id="@+id/canvas_image"
            style="@style/CanvasImageStyle"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:layout_centerInParent="true"
            android:layout_margin="0dp"
            android:adjustViewBounds="true"
            tools:src="@drawable/demo_image2" />

    </RelativeLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1">

    </LinearLayout>
</LinearLayout>

调整视图大小的代码:

 squareImageView.setImageBitmap(getResultBitmap());
            squareBoxHolder.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
                @Override
                public boolean onPreDraw() {
                    squareBoxHolder.getViewTreeObserver().removeOnPreDrawListener(this);
                    Log.i(TAG, "onPreDraw: squareBoxHolder");
                    squareBoxHolderSize = new Point(squareBoxHolder.getMeasuredWidth(), squareBoxHolder.getMeasuredHeight());
                    return true;
                }
            });
            squareImageView.getViewTreeObserver().addOnPreDrawListener(new ViewTreeObserver.OnPreDrawListener() {
                @Override
                public boolean onPreDraw() {
                    squareImageView.getViewTreeObserver().removeOnPreDrawListener(this);
                    Log.i(TAG, "onPreDraw: squareImageView");
                    int imageWidth = squareImageView.getMeasuredWidth();
                    int imageHeight = squareImageView.getMeasuredHeight();
                    int size;
                    ViewGroup.LayoutParams layoutParams = squareImageView.getLayoutParams();
                    if (imageWidth > imageHeight) {
                        if (imageWidth > squareBoxHolderSize.y) {
                            size = squareBoxHolderSize.y;
                            layoutParams.width = size;
                            squareImageView.setLayoutParams(layoutParams);
                        } else {
                            size = imageWidth;
                        }
                    } else {
                        if (imageHeight > squareBoxHolderSize.x) {
                            size = squareBoxHolderSize.x;
                            layoutParams.height = size;
                            squareImageView.setLayoutParams(layoutParams);
                        } else {
                            size = imageHeight;
                        }
                    }

                    layoutParams = squareBox.getLayoutParams();
                    layoutParams.height = size;
                    layoutParams.width = size;
                    squareBox.setLayoutParams(layoutParams);
                    return true;
                }
            });