Overlay text over imageview in framelayout program

问题:

I am trying to implement a textview over an image in a framelayout at the center and bottom of the layout as it is seen here:

http://developer.android.com/resources/articles/layout-tricks-merge.html

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"
 android:layout_width="fill_parent"
 android:layout_height="fill_parent">

<ImageView  
    android:layout_width="fill_parent" 
    android:layout_height="fill_parent" 

    android:scaleType="center"
    android:src="@drawable/golden_gate" />

<TextView
    android:layout_width="wrap_content" 
    android:layout_height="wrap_content" 
    android:layout_marginBottom="20dip"
    android:layout_gravity="center_horizontal|bottom"

    android:padding="12dip"

    android:background="#AA000000"
    android:textColor="#ffffffff"

    android:text="Golden Gate" />

</FrameLayout>

I am trying to implement this programmatically but with no luck.. I always get the textview on the top left corner..can anyone help? Here is my code:

FrameLayout frameLay = new FrameLayout(MainScreen.this);                            
LayoutParams layoutParamsFrame = new LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);

frameLay.setLayoutParams(layoutParamsFrame);

LinearLayout.LayoutParams layoutParamsImage= new LinearLayout.LayoutParams(LayoutParams.FILL_PARENT, LayoutParams.FILL_PARENT);

ImageView imageView= new ImageView(MainScreen.this);
imageView.setImageResource(R.drawable.movie);   
imageView.setLayoutParams(layoutParamsImage);

TextView theText=new TextView(MainScreen.this);
theText.setText("GOLDEN Gate");
theText.setTextColor(Color.WHITE);                           
theText.setTypeface(Typeface.DEFAULT_BOLD); 

LayoutParams layoutParamsText= new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);

theText.setLayoutParams(layoutParamsText);

theText.setGravity(Gravity.CENTER_HORIZONTAL|Gravity.BOTTOM);

frameLay.addView(theText);
frameLay.addView(imageView);

回答1:

All you need to do ias make the textview to fill the parent like

LayoutParams layoutParamsText= new LayoutParams(LayoutParams.FILL__PARENT, 
        LayoutParams.FILL_PARENT); 

When you set gravity to the textview, it mean you are telling the textview where to position its children. But since your textview only has the size of your text, the gravity wont show any difference. So just make the textview to fill the parent.

But I think RelativeLayout is a lot more suitable for this than the FrameLayout. Using the RelativeLayout this is how it would look

RelativeLayout rLayout = new RelativeLayout(this);
LayoutParams rlParams = new LayoutParams(LayoutParams.FILL_PARENT
        ,LayoutParams.FILL_PARENT); 
rLayout.setLayoutParams(rlParams);

ImageView image= new ImageView(this); 
image.setImageResource(R.drawable.icon);    
image.setLayoutParams(rlParams);

RelativeLayout.LayoutParams tParams = new RelativeLayout.LayoutParams
        (LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
tParams.addRule(RelativeLayout.CENTER_HORIZONTAL, RelativeLayout.TRUE);
tParams.addRule(RelativeLayout.ALIGN_PARENT_BOTTOM, RelativeLayout.TRUE);
TextView text=new TextView(this); 
text.setText("GOLDEN Gate"); 
text.setTextColor(Color.WHITE);                            
text.setTypeface(Typeface.DEFAULT_BOLD);
text.setLayoutParams(tParams);

rLayout.addView(image);
rLayout.addView(text);
setContentView(rLayout);

回答2:

Instead of a FrameLayout, you may want to try using a RelativeLayout as the container. That way, you can place the overlaying text anywhere you want. What should work for you is to assign the following to your TextView within a RelativeLayout:

android:layout_alignParentBottom="true" and android:layout_centerInParent="true"

You can then fine tune the placement with margins.