添加视图后刷新线性布局

您可以在代码中签入以下内容:

• 上 View setLayoutParameter 方法与适当的 ViewGroup.LayoutParameter .
• 查看 s、 确保您是在UI线程上执行的。为此,可以使用父 的 post 方法。

TextView 在启动时短暂延迟后:

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);
    }
}

我也遇到同样的问题,并注意到在invalidate之后没有调用重写的onMeasure()方法。所以我在LinearLayout中创建了自己的子例程,并在invalidate()方法之前调用了它。

以下是垂直线性布局的代码:

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);
}

必须在style.xml中设置透明颜色

<color name="transparent">#00000000</color>

在代码中只需调用

LinearLayout ll = (LinearLayout) findViewById(R.id.noteList);
ll.setBackgroundColor(getResources().getColor(R.color.transparent));
ll.invalidate();

如果你有可提取的背景电话

ll.setBackgroundResource(R.drawable.your_drawable);