动态更改视图宽度不起作用
Change width of view dynamically doesn't work
我将主要布局分为 4 个部分。第一部分是一个图像视图,它有 layout_weight="2" 和两个线性布局 layout_weight="1" 每一个。在每个线性布局中,都有 2 个水平方向的 CardView,我想以相等的宽度和高度显示它们。
我像下面这样更改每个 CardView 的宽度:
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);
}
你知道问题出在哪里吗?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>
如果您希望该视图是方形的,最好通过扩展目标小部件来创建它 class 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);
}
}
只需指定视图的宽度,它就会将其作为高度来形成一个正方形。
发生这种情况是因为尚未调整视图大小,试试这个:
@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);
}
}
});
}
您在屏幕上绘制之前提前获得视图高度。更好的方法是首先使用这样的观察器获取屏幕宽度
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
}
});
您可以关注 this 话题了解更多详情
试试这个,你就会知道如何在 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>
如果您的问题是将视图显示为 Square
,即宽度和高度应该相等,您可以轻松操作 OnMeasure()
视图方法。
由于您的观点是CardView
,我正在修改它,
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
}
}
你就大功告成 :) 定义 width
并且 height
将等于 width
。
我将主要布局分为 4 个部分。第一部分是一个图像视图,它有 layout_weight="2" 和两个线性布局 layout_weight="1" 每一个。在每个线性布局中,都有 2 个水平方向的 CardView,我想以相等的宽度和高度显示它们。
我像下面这样更改每个 CardView 的宽度:
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);
}
你知道问题出在哪里吗?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>
如果您希望该视图是方形的,最好通过扩展目标小部件来创建它 class 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);
}
}
只需指定视图的宽度,它就会将其作为高度来形成一个正方形。
发生这种情况是因为尚未调整视图大小,试试这个:
@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);
}
}
});
}
您在屏幕上绘制之前提前获得视图高度。更好的方法是首先使用这样的观察器获取屏幕宽度
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
}
});
您可以关注 this 话题了解更多详情
试试这个,你就会知道如何在 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>
如果您的问题是将视图显示为 Square
,即宽度和高度应该相等,您可以轻松操作 OnMeasure()
视图方法。
由于您的观点是CardView
,我正在修改它,
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
}
}
你就大功告成 :) 定义 width
并且 height
将等于 width
。