android 动态更改视图宽度无效

uxhixvfz  于 2023-05-05  发布在  Android
关注(0)|答案(5)|浏览(220)

我将主要布局分为四个部分。第一部分是一个图像视图,它具有layout_weight=“2”和两个线性布局,每个布局的layout_weight=“1”。在每一个线性布局有2 CardViews,水平方向,我想显示他们与相等的宽度和高度。

我改变每个CardView的宽度如下:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.home_page);

    CardView cardView1 = (CardView) findViewById(R.id.cardView1);
    ViewGroup.LayoutParams params = cardView1.getLayoutParams();

    params.width = params.height; // params.height == -1 ???
    cardView1.setLayoutParams(params);
}

你知道是什么问题吗?谢谢
XML文件是:

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
android:orientation="vertical"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:weightSum="4">

<ImageView
    android:id="@+id/userImage"
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:layout_weight="2"/>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:orientation="horizontal"
    android:layout_weight="1"
    android:weightSum="2">

    <android.support.v7.widget.CardView
        android:id="@+id/cardView1"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        app:cardCornerRadius="4dp"
        android:elevation="5dp"
        app:cardElevation="10dp"
        android:paddingBottom="15dp"
        android:paddingEnd="15dp"
        android:paddingLeft="15dp"
        android:paddingRight="15dp"
        android:paddingStart="15dp"
        android:paddingTop="15dp"
        android:layout_margin="15dp"
        app:cardBackgroundColor="?attr/colorButtonNormal">

        <TextView
            android:id="@+id/textView1"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="1"/>
    </android.support.v7.widget.CardView>

    <android.support.v7.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:id="@+id/cardView2"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:elevation="5dp"
        card_view:cardCornerRadius="4dp"
        card_view:cardElevation="10dp"
        android:paddingBottom="15dp"
        android:paddingEnd="15dp"
        android:paddingLeft="15dp"
        android:paddingRight="15dp"
        android:paddingStart="15dp"
        android:paddingTop="15dp"
        android:layout_margin="15dp"
        card_view:cardBackgroundColor="?attr/colorButtonNormal">

        <TextView
            android:id="@+id/textView2"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="2"/>
    </android.support.v7.widget.CardView>
</LinearLayout>

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="0dp"
    android:orientation="horizontal"
    android:layout_weight="1"
    android:weightSum="2">

    <android.support.v7.widget.CardView
        android:id="@+id/cardView3"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:elevation="5dp"
        app:cardCornerRadius="4dp"
        android:background="@color/cardview_dark_background"
        app:cardBackgroundColor="?attr/colorButtonNormal"
        app:cardElevation="10dp"
        android:paddingBottom="15dp"
        android:paddingEnd="15dp"
        android:paddingLeft="15dp"
        android:paddingRight="15dp"
        android:paddingStart="15dp"
        android:paddingTop="15dp"
        android:layout_margin="15dp">

        <TextView
            android:id="@+id/textView3"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="3"/>
    </android.support.v7.widget.CardView>

    <android.support.v7.widget.CardView
        xmlns:card_view="http://schemas.android.com/apk/res-auto"
        android:id="@+id/cardView4"
        android:layout_width="0dp"
        android:layout_height="match_parent"
        android:layout_weight="1"
        android:elevation="5dp"
        card_view:cardCornerRadius="4dp"
        card_view:cardElevation="10dp"
        android:paddingBottom="15dp"
        android:paddingEnd="15dp"
        android:paddingLeft="15dp"
        android:paddingRight="15dp"
        android:paddingStart="15dp"
        android:paddingTop="15dp"
        android:layout_margin="15dp"
        card_view:cardBackgroundColor="?attr/colorButtonNormal">

        <TextView
            android:id="@+id/textView4"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:text="4"/>
    </android.support.v7.widget.CardView>
</LinearLayout>
h22fl7wq

h22fl7wq1#

在屏幕上绘制之前,您将视图高度提前。更好的方法是首先使用观察器获取屏幕宽度,如下所示

view.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
            @Override
            public void onGlobalLayout() {
                view.getViewTreeObserver().removeOnGlobalLayoutListener(this);
                view.getWidth(); //width is ready here
                 // assign your image view the same height
                // divide this width by 2 and assign same height width to your cars views 
            }
        });

你可以按照this线程了解更多细节

dba5bblo

dba5bblo2#

发生这种情况是因为视图尚未调整大小,请尝试以下操作:

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);

    final CardView cardView1 = (CardView) findViewById(R.id.cardView1);

    cardView1.getViewTreeObserver().addOnGlobalLayoutListener(new ViewTreeObserver.OnGlobalLayoutListener() {
        @Override
        public void onGlobalLayout() {
            // remove the layout listener
            if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.JELLY_BEAN) {
                cardView1.getViewTreeObserver().removeOnGlobalLayoutListener(this);
            } else {
                cardView1.getViewTreeObserver().removeGlobalOnLayoutListener(this);
            }

            final int height = cardView1.getHeight(); 
            if (height >= 0) {
                // use the linearLayout LayoutParams
                LinearLayout.LayoutParams newParams =  new LinearLayout.LayoutParams(height, height);
                cardView1.setLayoutParams(newParams);
            }
        }
    });
}
yrwegjxp

yrwegjxp3#

如果你的问题是将你的视图显示为Square,即宽度和高度应该相等,你可以很容易地操作OnMeasure()视图方法。
因为你的视图是CardView,我修改了它,

import android.content.Context;
import android.support.v7.widget.CardView;
import android.util.AttributeSet;

public class SquareCardView extends CardView {

    public SquareCardView(Context context) {
        super(context);
    }

    public SquareCardView(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public SquareCardView(Context context, AttributeSet attrs, int defStyle) {
        super(context, attrs, defStyle);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);

        int width = getMeasuredWidth();
        //noinspection SuspiciousNameCombination
        setMeasuredDimension(width, width); // here comes manipulation
    }
}

定义widthheight等于width

3pvhb19x

3pvhb19x4#

如果你希望视图是正方形的,最好通过扩展目标widget类来创建它,如下所示:

public  class SquareView extends  View{

    public SquareView(Context context) {
        super(context);
    }

    @Override
    public void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, widthMeasureSpec);
    }
}

只要指定视图的宽度,它就会将其作为高度来形成一个正方形。

2g32fytz

2g32fytz5#

尝试一下,你会知道如何在LinearLayout中使用权重。

<LinearLayout
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:orientation="vertical"
    android:weightSum="2">

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

        <!--Place your image view here-->

    </LinearLayout>

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="0dp"
        android:layout_weight="1"
        android:orientation="vertical"
        android:weightSum="2">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:orientation="horizontal"
            android:weightSum="2">

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

                <!--CardView 1st-->

            </LinearLayout>

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

                <!--CardView 2nd-->
            </LinearLayout>

        </LinearLayout>

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="0dp"
            android:layout_weight="1"
            android:orientation="horizontal"
            android:weightSum="2">

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

                <!--CardView 3rd-->

            </LinearLayout>

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

                <!--CardView 4th-->

            </LinearLayout>

        </LinearLayout>

    </LinearLayout>

</LinearLayout>

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