RelativeLayout的无法正常更新的宽度自定义视图 [英] RelativeLayout not properly updating width of custom view
本文介绍了RelativeLayout的无法正常更新的宽度自定义视图的处理方法，对大家解决问题具有一定的参考价值，需要的朋友们下面随着小编来一起学习吧！
问题描述
我有用于使其中一个维度这个容器类，宽度或高度，另一个尺寸的比率。例如，我要一个16：9的布局容器，宽度为match_parent。但是，使用高度match_parent时，机器人似乎并没有正确地重新布局本身。当我设置的高度是宽度的一切的比率是好的！反之亦然，这是行不通的。这是怎么回事？
公共类RatioLayout扩展的ViewGroup {
私人浮动率= 1.6222f; // 4×3的默认。 1.78是16×9
公众持股量getRatio（）{回报率; }
公共无效setRatio（浮动比率）{
this.ratio =比;
requestLayout（）;
}
公共RatioLayout（上下文的背景下）{
这（背景下，NULL）;
}
公共RatioLayout（上下文的背景下，ATTRS的AttributeSet）{
这（背景下，ATTRS，0）;
}
公共RatioLayout（上下文的背景下，ATTRS的AttributeSet，诠释defStyle）{
超（背景下，ATTRS，defStyle）;
}
@覆盖
保护无效onMeasure（INT widthMeasureSpec，诠释heightMeasureSpec）{
Log.i（比率，/ onMeasure）;
INT宽度= MeasureSpec.getSize（widthMeasureSpec）;
INT高= MeasureSpec.getSize（heightMeasureSpec）;
INT widthMode = MeasureSpec.getMode（widthMeasureSpec）;
INT heightMode = MeasureSpec.getMode（heightMeasureSpec）;
// INT正好= MeasureSpec.EXACTLY; // 1073741824
// INT atMost = MeasureSpec.AT_MOST; // -2147483648
// INT UNSPEC = MeasureSpec.UNSPECIFIED; // 0
宽度= Math.round（高*比）;
widthMeasureSpec = MeasureSpec.makeMeasureSpec（宽，MeasureSpec.EXACTLY）;
heightMeasureSpec = MeasureSpec.makeMeasureSpec（高度，MeasureSpec.EXACTLY）;
setMeasuredDimension（widthMeasureSpec，heightMeasureSpec）;
INT MW = getMeasuredWidth（）;
INT MH = getMeasuredHeight（）;
Log.i（比率，MW：+ MW +，MH：+ MH）;
}
@覆盖
保护无效onLayout（布尔改变，诠释L，INT T，INT R，int b）在{
Log.i（比率，/ onLayout）;
Log.i（比率，升+ 1 +，厚度：+ T +，R：+ R +，B：+ b）的;
Log.i（比率，MW：+ getMeasuredWidth（）+，MH：+ getMeasuredHeight（））;
Log.i（比率，瓦特：+的getWidth（）+，MW：+的getHeight（））;
}
}
要看到它在行动中，使用的布局是这样的：
＆LT; RelativeLayout的的xmlns：机器人=http://schemas.android.com/apk/res/android
的xmlns：工具=http://schemas.android.com/tools
机器人：layout_width =match_parent
机器人：layout_height =match_parent
工具：上下文=MainActivity。＆GT;
＆LT; com.example.RatioLayout
机器人：ID =@ + ID /图像
机器人：layout_width =0dp
机器人：layout_height =match_parent
机器人：layout_marginBottom =100dp
机器人：layout_marginTop =100dp
机器人：后台=＃FFFF00FF/＆GT;
＆LT; / RelativeLayout的＆GT;
这将是我的活动：
日志输出：
I /比（9445）：/ onMeasure
I /比（9445）：分子量：1087，MH：670
I /比（9445）：/ onMeasure
I /比（9445）：MW：655，MH：404
I /比（9445）：/ onLayout
I /比（9445）：L：0，T：133，R：1087，B：537
I /比（9445）：MW：655，MH：404
I /比（9445）：W：1087，MW：404＆LT; ---没有原因，这不应该是655
为什么Android的不尊敬我的最新measuredWidth，但使用的是旧版本，但最新的高度？
编辑：更新。使RatioLayout的父不会 RelativeLayout的，但一个LinearLayout中或的FrameLayout给了我正确的行为。出于某种原因，RelativeLayout的是高速缓存measuredWidth和没有使用最新的。
编辑2：在RelativeLayout.onLayout这一评论似乎证实了我这是高速缓存，我相信这是一个错误
@覆盖
保护无效onLayout（布尔改变，诠释L，INT T，INT R，int b）在{
//布局实际上已经被执行及职位
//缓存。应用缓存值给孩子们。
诠释计数= getChildCount（）;
// TODO：我们需要找到另一种方式来实现RelativeLayout的
//这个实现无法处理每一个案件
@覆盖
保护无效onMeasure（INT widthMeasureSpec，诠释heightMeasureSpec）{
最后编辑确定。我放弃。这是RelativeLayout的一个合法的错误。这code类修复它，但它造成的toRightOf性能问题。周围的工作中，我发现了窝这个RatioLayout到像LinerLayout另一个ViewGroup中。 code对于那些好奇
@覆盖
保护无效onMeasure（INT widthMeasureSpec，诠释heightMeasureSpec）{
Log.i（比率，/ onMeasure）;
INT宽度= MeasureSpec.getSize（widthMeasureSpec）;
INT高= MeasureSpec.getSize（heightMeasureSpec）;
INT widthMode = MeasureSpec.getMode（widthMeasureSpec）;
INT heightMode = MeasureSpec.getMode（heightMeasureSpec）;
// INT正好= MeasureSpec.EXACTLY; // 1073741824
// INT atMost = MeasureSpec.AT_MOST; // -2147483648
// INT UNSPEC = MeasureSpec.UNSPECIFIED; // 0
宽度= Math.round（高*比）;
widthMeasureSpec = MeasureSpec.makeMeasureSpec（宽，MeasureSpec.EXACTLY）;
heightMeasureSpec = MeasureSpec.makeMeasureSpec（高度，MeasureSpec.EXACTLY）;
setMeasuredDimension（widthMeasureSpec，heightMeasureSpec）;
如果（的getParent（）的instanceof RelativeLayout的）{
RelativeLayout.LayoutParams PARAMS =（RelativeLayout.LayoutParams）getLayoutParams（）;
类＆LT;＆GT; clazz所= RelativeLayout.LayoutParams.class;
尝试 {
现场留下= clazz.getDeclaredField（MLEFT）;
场右侧= clazz.getDeclaredField（mRight）;
left.setAccessible（真正的）;
right.setAccessible（真正的）;
INT L = left.getInt（PARAMS）;
如果（L == -1）L = params.leftMargin; //如果该值未初始化，将其设置为0;
如果（升== -1）升= 0; //如果该值未初始化，将其设置为0;
//设置这似乎打破layout_marginLeft属性。
right.setInt（参数，可以升+ getMeasuredWidth（））;
}赶上（NoSuchFieldException E）{
Log.e（理性，错误，E）;
}赶上（抛出：IllegalArgumentException E）{
Log.e（理性，错误，E）;
}赶上（IllegalAccessException E）{
Log.e（理性，错误，E）;
}
}
INT MW = getMeasuredWidth（）;
INT MH = getMeasuredHeight（）;
lastWidth =兆瓦;
Log.i（比率，MW：+ MW +，MH：+ MH）;
}
解决方案
其实我已经尝试做你正在尝试做之前，也就是，让完全是一个查看要尽可能大，同时保持某些方面比（即方形或4：3或类似的东西）。
我的问题是，当我的观点是在一个滚动型尺寸得到了计算错误。我无法弄清楚这一个，但我会后我的code以下，以防万一它帮助。这真的很相似，你的code，但我从的FrameLayout 继承和我最终调用 super.onMeasure（）。
我仔细检查我就是用这个项目，我也确实有它的直接子 RelativeLayout的。
Java的：
/ **
*一个的FrameLayout它试图在保持其宽度和高度之间的给定的比例要尽可能大。
*公式：高度=宽度/比率;
* 用法：
* 1）设置layout_width和layout_height为match_parent
* 2）对于4：3比如，设置比例为4/3 = 1.333333等。或者不指定，这将是默认广场。
* /
公共类RatioFrameLayout扩展的FrameLayout
{
私人最终静态浮动DEFAULT_RATIO = 1F;
私人流通股比例;
测量= FALSE私人布尔;
公共RatioFrameLayout（上下文的背景下）
{
超（上下文）;
}
公共RatioFrameLayout（上下文的背景下，ATTRS的AttributeSet）
{
超（背景下，ATTRS）;
readAttributes（背景下，ATTRS）;
}
公共RatioFrameLayout（上下文的背景下，ATTRS的AttributeSet，INT defStyle）
{
超（背景下，ATTRS，defStyle）;
readAttributes（背景下，ATTRS）;
}
私人无效readAttributes（上下文的背景下，ATTRS的AttributeSet）
{
TypedArray A = context.obtainStyledAttributes（ATTRS，R.styleable.RatioFrameLayout）;
字符串值= a.getString（R.styleable.RatioFrameLayout_ratio）;
尝试
{
比= Float.parseFloat（值）;
}
赶上（例外五）
{
比= DEFAULT_RATIO;
}
a.recycle（）;
}
公众持股量getRatio（）
{
回报率;
}
公共无效setRatio（浮动比率）
{
this.ratio =比;
}
@覆盖
保护无效onMeasure（INT widthMeasureSpec，INT heightMeasureSpec）
{
super.onMeasure（widthMeasureSpec，heightMeasureSpec）;
INT targetWidth = getMeasuredWidth（）;
INT targetHeight = Math.round（（浮点）getMeasuredWidth（）/比例）;
如果（targetHeight＆GT; getMeasuredHeight（）＆安培;＆安培;！getMeasuredHeight（）= 0）
{
targetWidth = Math.round（getMeasuredHeight（）*比率）;
targetHeight = getMeasuredHeight（）;
}
super.onMeasure（MeasureSpec.makeMeasureSpec（targetWidth，MeasureSpec.EXACTLY），MeasureSpec.makeMeasureSpec（targetHeight，MeasureSpec.EXACTLY））;
}
私人无效printMeasureSpec（字符串描述，int值）
{
INT模式= MeasureSpec.getMode（值）;
字符串模式名=模式== MeasureSpec.AT_MOST？ 最多
：模式== MeasureSpec.EXACTLY？ 正是：未指定;
DLog.d（的String.Format（测量规格％s的，模式=％S，大小=％D，描述，模式名，MeasureSpec.getSize（值）））;
}
}
attrs.xml ：
＆LT;资源＆GT;
＆LT;申报，设置样式名称=RatioFrameLayout＆GT;
＆LT; attr指示NAME =比FORMAT =字符串|引用/＆GT;
＆LT; /申报，设置样式＆GT;
＆LT; /资源＆GT;
I have this container class that is used to make one of the dimensions, either the width or height, a ratio of the other dimension. For instance, I want a 16:9 layout container where the width is "match_parent". However, when using the height as "match_parent", Android does not seem to properly relayout itself. When I set the height to be a ratio of the width everything is fine! Vise versa and it doesn't work. What's going on?
public class RatioLayout extends ViewGroup {
private float ratio = 1.6222f; // 4 x 3 default. 1.78 is 16 x 9
public float getRatio() { return ratio; }
public void setRatio(float ratio) {
this.ratio = ratio;
requestLayout();
}
public RatioLayout(Context context) {
this(context, null);
}
public RatioLayout(Context context, AttributeSet attrs) {
this(context, attrs, 0);
}
public RatioLayout(Context context, AttributeSet attrs, int defStyle) {
super(context, attrs, defStyle);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.i("Ratio", "/onMeasure");
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
// int exactly = MeasureSpec.EXACTLY; // 1073741824
// int atMost = MeasureSpec.AT_MOST; // -2147483648
// int unspec = MeasureSpec.UNSPECIFIED; // 0
width = Math.round(height * ratio);
widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
setMeasuredDimension(widthMeasureSpec, heightMeasureSpec);
int mw = getMeasuredWidth();
int mh = getMeasuredHeight();
Log.i("Ratio", "mw: " + mw + ", mh: " + mh);
}
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
Log.i("Ratio", "/onLayout");
Log.i("Ratio", "l: " + l + ", t: " + t + ", r:" + r + ", b:" + b);
Log.i("Ratio", "mw: " + getMeasuredWidth() + ", mh:" + getMeasuredHeight());
Log.i("Ratio", "w: " + getWidth() + ", mw:" + getHeight());
}
}
To see it in action, use a layout like this:
<RelativeLayout 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"
tools:context=".MainActivity" >
<com.example.RatioLayout
android:id="@+id/image"
android:layout_width="0dp"
android:layout_height="match_parent"
android:layout_marginBottom="100dp"
android:layout_marginTop="100dp"
android:background="#FFFF00FF" />
</RelativeLayout>
And this would be my Activity:
Logging output:
I/Ratio (9445): /onMeasure
I/Ratio (9445): mw: 1087, mh: 670
I/Ratio (9445): /onMeasure
I/Ratio (9445): mw: 655, mh: 404
I/Ratio (9445): /onLayout
I/Ratio (9445): l: 0, t: 133, r:1087, b:537
I/Ratio (9445): mw: 655, mh:404
I/Ratio (9445): w: 1087, mw:404 <--- NO reason this should not be 655
Why would Android not honor my latest measuredWidth but use an older version but the latest height?
EDIT: Updated. Make the parent of the RatioLayout NOT a RelativeLayout but a LinearLayout or FrameLayout gives me the correct behavior. For some reason RelativeLayout is "caching" the measuredWidth and not using the most current.
EDIT 2: This comment in RelativeLayout.onLayout seems to confirm my "it's caching" which I believe is a bug
@Override
protected void onLayout(boolean changed, int l, int t, int r, int b) {
// The layout has actually already been performed and the positions
// cached. Apply the cached values to the children.
int count = getChildCount();
// TODO: we need to find another way to implement RelativeLayout
// This implementation cannot handle every case
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
FINAL EDIT Ok. I give up. This is a legit bug in RelativeLayout. This code kind of fixes it, but it creates issues with the toRightOf properties. The work around that I found was to nest this RatioLayout into another ViewGroup like LinerLayout. Code for those curious
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
Log.i("Ratio", "/onMeasure");
int width = MeasureSpec.getSize(widthMeasureSpec);
int height = MeasureSpec.getSize(heightMeasureSpec);
int widthMode = MeasureSpec.getMode(widthMeasureSpec);
int heightMode = MeasureSpec.getMode(heightMeasureSpec);
// int exactly = MeasureSpec.EXACTLY; // 1073741824
// int atMost = MeasureSpec.AT_MOST; // -2147483648
// int unspec = MeasureSpec.UNSPECIFIED; // 0
width = Math.round(height * ratio);
widthMeasureSpec = MeasureSpec.makeMeasureSpec(width, MeasureSpec.EXACTLY);
heightMeasureSpec = MeasureSpec.makeMeasureSpec(height, MeasureSpec.EXACTLY);
setMeasuredDimension(widthMeasureSpec, heightMeasureSpec);
if (getParent() instanceof RelativeLayout) {
RelativeLayout.LayoutParams params = (RelativeLayout.LayoutParams)getLayoutParams();
Class<?> clazz = RelativeLayout.LayoutParams.class;
try {
Field left = clazz.getDeclaredField("mLeft");
Field right = clazz.getDeclaredField("mRight");
left.setAccessible(true);
right.setAccessible(true);
int l = left.getInt(params);
if (l == -1) l = params.leftMargin; // if the value is uninitialized, set it to 0;
if (l == -1) l = 0; // if the value is uninitialized, set it to 0;
// setting this seems to break the layout_marginLeft properties.
right.setInt(params, l + getMeasuredWidth());
} catch (NoSuchFieldException e) {
Log.e("Ration", "error", e);
} catch (IllegalArgumentException e) {
Log.e("Ration", "error", e);
} catch (IllegalAccessException e) {
Log.e("Ration", "error", e);
}
}
int mw = getMeasuredWidth();
int mh = getMeasuredHeight();
lastWidth = mw;
Log.i("Ratio", "mw: " + mw + ", mh: " + mh);
}
解决方案
I've actually tried to do exactly what you're trying to do before, that is, make a View be as big as possible while retaining some aspect ratio (i.e. square or 4:3 or something like that).
My problem was that when my View was in a ScrollView the size got computed incorrectly. I wasn't able to figure this one out, but I'll post my code below just in case it helps. It's really similar to your code, but I'm inheriting from FrameLayout and I end up calling super.onMeasure().
I double checked the project I was using this in, and I do actually have it as a direct child of RelativeLayout.
Java:
/**
* A FrameLayout which tries to be as big as possible while maintaining a given ratio between its width and height.
* Formula: Height = Width / ratio;
* Usage:
* 1) Set layout_width and layout_height to "match_parent"
* 2) For 4:3 for example, set ratio to 4/3 = 1.333333 etc. Or don't specify, and it will be square by default.
*/
public class RatioFrameLayout extends FrameLayout
{
private final static float DEFAULT_RATIO = 1f;
private float ratio;
private boolean measured = false;
public RatioFrameLayout(Context context)
{
super(context);
}
public RatioFrameLayout(Context context, AttributeSet attrs)
{
super(context, attrs);
readAttributes(context, attrs);
}
public RatioFrameLayout(Context context, AttributeSet attrs, int defStyle)
{
super(context, attrs, defStyle);
readAttributes(context, attrs);
}
private void readAttributes(Context context, AttributeSet attrs)
{
TypedArray a = context.obtainStyledAttributes(attrs, R.styleable.RatioFrameLayout);
String value = a.getString(R.styleable.RatioFrameLayout_ratio);
try
{
ratio = Float.parseFloat(value);
}
catch (Exception e)
{
ratio = DEFAULT_RATIO;
}
a.recycle();
}
public float getRatio()
{
return ratio;
}
public void setRatio(float ratio)
{
this.ratio = ratio;
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec)
{
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
int targetWidth = getMeasuredWidth();
int targetHeight = Math.round((float)getMeasuredWidth() / ratio);
if (targetHeight > getMeasuredHeight() && getMeasuredHeight() != 0)
{
targetWidth = Math.round(getMeasuredHeight() * ratio);
targetHeight = getMeasuredHeight();
}
super.onMeasure(MeasureSpec.makeMeasureSpec(targetWidth, MeasureSpec.EXACTLY), MeasureSpec.makeMeasureSpec(targetHeight, MeasureSpec.EXACTLY));
}
private void printMeasureSpec(String description, int value)
{
int mode = MeasureSpec.getMode(value);
String modeName = mode == MeasureSpec.AT_MOST ? "AT_MOST"
: mode == MeasureSpec.EXACTLY ? "EXACTLY" : "UNSPECIFIED";
DLog.d(String.format("Measure spec for %s, mode = %s, size = %d", description, modeName, MeasureSpec.getSize(value)));
}
}
attrs.xml:
<resources>
<declare-styleable name="RatioFrameLayout">
<attr name="ratio" format="string|reference" />
</declare-styleable>
</resources>
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