adding dynamic view using WindowManager.addView

问题

I have a code on ICS for tablets. I want to add a Imageview dynamicly to a fragment. The fragment already contains preferencelist. The code for adding the view dynamically is as follows. I am coding this drag and drop functionality. This part of the code is taken from TouchInterceptor.java file from android music app.

mWindowParams = new WindowManager.LayoutParams();
mWindowParams.gravity = Gravity.TOP ;
mWindowParams.x = 0;
mWindowParams.y = y
mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
    | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
    | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
    | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN;
mWindowParams.format = PixelFormat.TRANSLUCENT;
mWindowParams.windowAnimations = 0;

ImageView v = new ImageView(mContext);
int backGroundColor = mContext.getResources().getColor(R.color.bg_background);
v.setBackgroundColor(backGroundColor);
v.setImageBitmap(bm);

mWindowManager = (WindowManager)mContext.getSystemService("window");
mWindowManager.addView(v, mWindowParams);

I am specifying the x coordinate of windowlayout param as 0. Eventthen when the view is displayed , itstead of displaying from the leftside of the fragment(the right pane) ,the view is displayed from middle of the right pane and is spanning to the right pane . What I am doing wrong ? Whats has to be done to correct this ?

回答1:

Try setting gravity to Gravity.TOP | Gravity.LEFT

回答2:

I m working exatly on the same code taken from the old Google Music open souce project.

Like you I guess, I had a TouchInterceptor in a fragment. My problem was that the fragment does not take all the screen widht, it has an other fragment on its left.

I tried a lot using mWindowParams.gravity to be able to specify an absolute x,y but I couldn't find a solution. Eventually I solved it with mWindowParams.horizontalMargin.

Here is the code I came up with:

private int getAbsoluteLeft(){
    ViewGroup parent;
    View child = this;
    int left_absolute_position = 0;
    try{
        while( (parent = (ViewGroup) child.getParent()) != null) {
            left_absolute_position += child.getLeft();
            child = parent;
        }
    }catch(ClassCastException e){
    }

    return left_absolute_position;
}

private void startDragging(Bitmap bm, int x, int y) {
    stopDragging();
    //build the view
    Context context = getContext();
    ImageView v = new ImageView(context);
    //int backGroundColor = context.getResources().getColor(R.color.dragndrop_background);
    //v.setBackgroundColor(backGroundColor);
    //v.setBackgroundResource(R.drawable.playlist_tile_drag);
    v.setPadding(0, 0, 0, 0);
    v.setImageBitmap(bm);
    mDragBitmap = bm;

    mWindowManager = (WindowManager)context.getSystemService(Context.WINDOW_SERVICE);

    //Build Params
    mWindowParams = new WindowManager.LayoutParams();
    mWindowParams.gravity = Gravity.TOP | Gravity.LEFT;
    mWindowParams.x = ( x - mDragPointX + mXOffset );
    mWindowParams.y = ( y - mDragPointY + mYOffset );

    DisplayMetrics metrics = new DisplayMetrics();
    mWindowManager.getDefaultDisplay().getMetrics(metrics);
    mWindowParams.horizontalMargin = (float)getAbsoluteLeft() / (float)metrics.widthPixels;

    mWindowParams.height = WindowManager.LayoutParams.WRAP_CONTENT;
    mWindowParams.width = WindowManager.LayoutParams.WRAP_CONTENT;
    mWindowParams.flags = WindowManager.LayoutParams.FLAG_NOT_FOCUSABLE
            | WindowManager.LayoutParams.FLAG_NOT_TOUCHABLE
            | WindowManager.LayoutParams.FLAG_KEEP_SCREEN_ON
            | WindowManager.LayoutParams.FLAG_LAYOUT_IN_SCREEN
            | WindowManager.LayoutParams.FLAG_LAYOUT_NO_LIMITS;
    mWindowParams.format = PixelFormat.TRANSLUCENT;
    mWindowParams.windowAnimations = 0;

    mWindowManager.addView(v, mWindowParams);
    mDragView = v;
}

The part I added is:

DisplayMetrics metrics = new DisplayMetrics();
mWindowManager.getDefaultDisplay().getMetrics(metrics);
mWindowParams.horizontalMargin = (float)getAbsoluteLeft() / (float)metrics.widthPixels;

This parameter mWindowParams.horizontalMargin specify the margin of the window from the specified gravity side (Gravity.Left) as a % € [0,1].

So with getAbsoluteLeft() I go up to the View tree to get the absolute distance of the list from the left side.

Dividing it by the window's width, you get percent of margin you need.

来源：https://stackoverflow.com/questions/9684275/adding-dynamic-view-using-windowmanager-addview