以编程方式使ImageView的底部边距不起作用

Question

marginBottom not working. It works but the margin is only a few space regardless of how much margin is applied. Why?

Java-code :

LinearLayout onepage= (LinearLayout) findViewById(R.id.onepage);

RelativeLayout bluegreen = new RelativeLayout(this);
p_ll = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);
bluegreen.setLayoutParams(p_ll);

//some other views that make up the whole page

//bottom most image
ImageButton migs = new ImageButton(this);
p_rl = new RelativeLayout.LayoutParams(ViewGroup.LayoutParams.WRAP_CONTENT, ViewGroup.LayoutParams.WRAP_CONTENT);
p_rl.addRule(RelativeLayout.CENTER_HORIZONTAL);
p_rl.setMargins(0, 0, 0, 20);
register.setLayoutParams(p_rl);
register.setImageResource(R.drawable.migs);
register.setPadding(0, 0, 0, 0);

bluegreen.addView(migs);

onepage.addView(bluegreen);

XML:

<LinearLayout
    android:id="@+id/onepage"
    android:layout_width="match_parent"
    android:layout_height="match_parent"        
    android:orientation="vertical"
    tools:context=".PageActivity" >
</LinearLayout>

Answer 1

Have you notice that in setMargins method parameters are in pixel and not in dp? take a look at android doc page

So depending of your device screen size but 20 px can be very small.

Don't forget to call requestLayout() to take in account margin changes.