android:TextView的LayoutParams使视图以编程方式消失 [英] android: LayoutParams for TextView makes the view disappear, programmatically
问题描述
我从不同的角度对此进行了探讨.基本上是这样的:
我已经为接口设计了XML模板，该接口需要以编程方式运行，因此在运行期间将动态填充该模板.
这里的问题是XML TextView有相当多的布局调整(有效)并且是必需的.但是，如果我实际上在代码中设置了它们，则TextView甚至都不会显示.
(顺便说一下，TextView嵌套在TableRow内部，因此是对weight的调用.) 我首先设计的XML模板(用作代码参考)是这样，它可以正常工作:
<TextView
android:id="@+id/txtviewWhiteBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:background="@drawable/textview_9patch_white"
android:gravity="center"
android:text="75"
android:textColor="@android:color/black"
android:layout_margin="20dp"
android:padding="20dp"
android:textSize="40dp" />
就像我说的那样，布局很完美. 但是，当我在代码中运行相同的布局并应用LayoutParams时，TextView消失了.
以下是相关代码段:
int textViewExampleID = 9001;
private TextView txtviewExample = new TextView(this);
private void buildTextView(){
LayoutParams paramsExample = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,1.0f);
txtviewExample.setId(textViewExampleID);
txtviewExample.setBackgroundResource(R.drawable.textview_9patch_white);
txtviewExample.setGravity(Gravity.CENTER);
txtviewExample.setTextColor(getResources().getColor(android.R.color.black));
paramsExample.setMargins(20, 20, 20, 20);
txtviewExample.setPadding(20, 20, 20, 20);
txtviewExample.setTextSize(40);
txtviewExample.setText("customExample");
//if I comment out the following line, this TextView displays.
//if I leave it in, it doesn't display.
txtviewExample.setLayoutParams(paramsExample);
}
我意识到LayoutParams有各种可用的类，并且我一直在与他们一起玩 LinearLayout.LayoutParams，TableView.LayoutParams，RelativeLayout.LayoutParams，LayoutParams本身... 无论我尝试哪种方法，任何调用"setLayoutParams"的尝试都会使整个TextView消失. 我在这里搜索过论坛，但还没有找到答案.这并非罕见.
好，那很痛苦，但我终于弄明白了.
要记住的最重要的事情(我刚刚意识到)是在LayoutParams的所有众多内容中，您需要使用与正在处理的视图的父级相关的一个，而不是与实际视图相关的一个. >
因此，在我的情况下，我试图使TextView边距正常工作，但是将其放置在TableRow内部.一个简单的更改就是确保使用的LayoutParams类型是TableRow的类型:
private void buildTextView(){
// the following change is what fixed it
TableRow.LayoutParams paramsExample = new TableRow.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,1.0f);
txtviewExample.setId(textViewExampleID);
txtviewExample.setBackgroundResource(R.drawable.textview_9patch_white);
txtviewExample.setGravity(Gravity.CENTER);
txtviewExample.setTextColor(getResources().getColor(android.R.color.black));
paramsExample.setMargins(20, 20, 20, 20);
txtviewExample.setPadding(20, 20, 20, 20);
txtviewExample.setTextSize(40);
txtviewExample.setText("customExample");
txtviewExample.setLayoutParams(paramsExample);
}
谢谢大家，希望这对其他人会派上用场，正如我在这里的论坛上看到的很多半相关问题一样，但并不是真正定义问题的一个.
I've hit this from various different angles. Basically the gist is this:
I've layed out a template in XML for an interface which NEEDS to be run programmatically, so it's going to be populated dynamically during the run.
The problem here, is that the XML TextView has quite a few layout tweaks (which work) and are necessary. But if I actually set them in code, the TextView doesn't even show up.
(The TextView, by the way, is nested inside a TableRow, thus the call to weight.) The XML template I designed first, to use as reference for the code is this, and it works just fine:
<TextView
android:id="@+id/txtviewWhiteBox"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_weight="1.0"
android:background="@drawable/textview_9patch_white"
android:gravity="center"
android:text="75"
android:textColor="@android:color/black"
android:layout_margin="20dp"
android:padding="20dp"
android:textSize="40dp" />
Like I said, that lays out perfectly. When I run the same layout in code though, and apply LayoutParams, the TextView disappears.
Here's the relevant snippet:
int textViewExampleID = 9001;
private TextView txtviewExample = new TextView(this);
private void buildTextView(){
LayoutParams paramsExample = new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,1.0f);
txtviewExample.setId(textViewExampleID);
txtviewExample.setBackgroundResource(R.drawable.textview_9patch_white);
txtviewExample.setGravity(Gravity.CENTER);
txtviewExample.setTextColor(getResources().getColor(android.R.color.black));
paramsExample.setMargins(20, 20, 20, 20);
txtviewExample.setPadding(20, 20, 20, 20);
txtviewExample.setTextSize(40);
txtviewExample.setText("customExample");
//if I comment out the following line, this TextView displays.
//if I leave it in, it doesn't display.
txtviewExample.setLayoutParams(paramsExample);
}
I realize there's all sorts of available classes for LayoutParams, and I've been playing with them all LinearLayout.LayoutParams, TableView.LayoutParams, RelativeLayout.LayoutParams, LayoutParams just by itself... No matter which one I try, any attempt at calling "setLayoutParams" renders the entire TextView gone. I've scoured the forums here, and haven't quite found the answer. This can't be THAT uncommon.
well, that was painful but I finally got it figured out.
The most important thing to remember (that I just realized) is that of all the myriads of LayoutParams, you need to use the one that relates to the PARENT of the view you're working on, not the actual view.
So in my case, I was trying to get the TextView margins working, but it was being put inside a TableRow. The one simple change was ensuring that the type of LayoutParams being used were the ones for TableRow:
private void buildTextView(){
// the following change is what fixed it
TableRow.LayoutParams paramsExample = new TableRow.LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT,1.0f);
txtviewExample.setId(textViewExampleID);
txtviewExample.setBackgroundResource(R.drawable.textview_9patch_white);
txtviewExample.setGravity(Gravity.CENTER);
txtviewExample.setTextColor(getResources().getColor(android.R.color.black));
paramsExample.setMargins(20, 20, 20, 20);
txtviewExample.setPadding(20, 20, 20, 20);
txtviewExample.setTextSize(40);
txtviewExample.setText("customExample");
txtviewExample.setLayoutParams(paramsExample);
}
Thanks guys, hopefully this will come in handy for somebody else down the line, as I saw a lot of semi-related questions in the forums here, but not one that really defines the problem.
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