我正在尝试动态地将视图添加到线性布局中。 通过getChildCount()查看,我发现视图已添加到布局中,但即使在布局上调用invalidate(),子项也没有显示出来。
我是否漏掉了什么?
我正在尝试动态地将视图添加到线性布局中。 通过getChildCount()查看,我发现视图已添加到布局中,但即使在布局上调用invalidate(),子项也没有显示出来。
我是否漏掉了什么?
您可以在代码中检查以下几点:
以下自包含示例会在启动后短暂延迟后添加一个 TextView:
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);
}
}
我遇到了同样的问题,发现在调用invalidate()方法后我的重写onMeasure()方法没有被调用。因此,我在LinearLayout中创建了自己的子程序,在调用invalidate()方法之前先调用它。
这是一个垂直LinearLayout的代码:
private void measure() {
if (this.getOrientation() == LinearLayout.VERTICAL) {
int h = 0;
int w = 0;
this.measureChildren(0, 0);
for (int i = 0; i < this.getChildCount(); i++) {
View v = this.getChildAt(i);
h += v.getMeasuredHeight();
w = (w < v.getMeasuredWidth()) ? v.getMeasuredWidth() : w;
}
height = (h < height) ? height : h;
width = (w < width) ? width : w;
}
this.setMeasuredDimension(width, height);
}
<color name="transparent">#00000000</color>
同时保留HTML标签。
LinearLayout ll = (LinearLayout) findViewById(R.id.noteList);
ll.setBackgroundColor(getResources().getColor(R.color.transparent));
ll.invalidate();
ll.setBackgroundResource(R.drawable.your_drawable);