添加视图后刷新 LinearLayout [英] Refreshing a LinearLayout after adding a view
本文介绍了添加视图后刷新 LinearLayout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
我正在尝试将视图动态添加到线性布局.我通过 getChildCount() 看到视图已添加到布局中,但即使在布局上调用 invalidate() 也不会让我看到孩子们.
I'm trying to add views dynamically to a linearlayout. I see through getChildCount() that the views are added to the layout, but even calling invalidate() on the layout doesn't give me the childs showed up.
我错过了什么吗?
推荐答案
您可以在代码中检查一些事情:
A couple of things you can check in your code:
- 在正在添加的 View 上,检查您是否调用了它的 setLayoutParameter 方法与适当的 ViewGroup.LayoutParameter.
- 当您添加新的 View 时,请确保您在 UI 线程上执行此操作.为此,您可以使用父 View 的 post 方法.
- On the View that is being added, check that you call its setLayoutParameter method with an appropriate ViewGroup.LayoutParameter.
- When you adding the new Views, make sure you are doing it on the UI thread. To do this, you can use the parent View's post method.
这个自包含的例子在短暂的延迟后添加了一个 TextView它开始:
This self contained example adds a TextView after a short delay when it starts:
import java.util.Timer;
import java.util.TimerTask;
import android.app.Activity;
import android.os.Bundle;
import android.view.ViewGroup;
import android.widget.LinearLayout;
import android.widget.TextView;
public class ProgrammticView extends Activity {
/** Called when the activity is first created. */
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
final LinearLayout layout = new LinearLayout(this);
layout.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.FILL_PARENT));
setContentView(layout);
// This is just going to programatically add a view after a short delay.
Timer timing = new Timer();
timing.schedule(new TimerTask() {
@Override
public void run() {
final TextView child = new TextView(ProgrammticView.this);
child.setText("Hello World!");
child.setLayoutParams(new ViewGroup.LayoutParams(
ViewGroup.LayoutParams.FILL_PARENT,
ViewGroup.LayoutParams.WRAP_CONTENT));
// When adding another view, make sure you do it on the UI
// thread.
layout.post(new Runnable() {
public void run() {
layout.addView(child);
}
});
}
}, 5000);
}
}
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