Android：如何使用x和y在屏幕下方的滚动视图中添加元素（并使其滚动）

Question

I'm trying to add an element to a screen in Android using X and Y co-ordinates that's beneath the screen but when it loads the screen won't scroll.

My code for the layout

<ScrollView  
xmlns:android="http://schemas.android.com/apk/res/android"  
android:layout_width="match_parent"
android:layout_height="match_parent"
android:fillViewport="true"
android:scrollbars="vertical"
android:id="@+id/ScrollView"
android:background="#16A901"
>

<RelativeLayout
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:id="@+id/inner"
    android:background="#b200C4"
    >

</RelativeLayout>
</ScrollView>

My Java code

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    setContentView(R.layout.activity_xycords);

    Display display = getWindowManager().getDefaultDisplay();
    Point size = new Point();
    display.getSize(size);
    int maxX = size.x; 
    int maxY = size.y;
    System.out.println("bar maxX "+maxX+" maxY "+maxY);

    ScrollView sv= (ScrollView)findViewById(R.id.ScrollView);

    RelativeLayout inner = (RelativeLayout)findViewById(R.id.inner);

    Button button = new Button(this);
    button.setBackgroundResource(R.drawable.black_rect_border_yellow);
    button.setText("Test 1 2 3");
    button.setX(10);
    button.setY(661);//652 is the maxY in my set up so this will obscure part of it

    LayoutParams wrap= new LayoutParams(LayoutParams.WRAP_CONTENT,LayoutParams.WRAP_CONTENT);
    wrap.setMargins(0, 0, 0, 0);
    //wrap.addRule(RelativeLayout.ALIGN_LEFT,R.id.vLine);
    //wrap.addRule(RelativeLayout.ALIGN_TOP,R.id.hLine);
    inner.addView(button, wrap);
}

I end up with a button where part of it is offscreen but it won't scroll to show the rest.

Any idea what I'm doing wrong?

Answer 1

You must set inner layout_height to a value greater than button y value:

...
inner.addView(button, wrap);

FrameLayout.LayoutParams params = (FrameLayout.LayoutParams)inner.getLayoutParams();
params.height = 661 + 48;
inner.setLayoutParams(params);