Question

我正在Android Studio中开发一个应用程序，该应用程序从RealtimeDatabase Firebase获取数据，并且具有以下方法，我可以在首次运行时加载所有数据，但是当UI不变时更新数据库时， >

ValueEventListener eventListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            for(DataSnapshot ds : dataSnapshot.getChildren()) {

                MapModel shiftMap = ds.getValue(MapModel.class);

                ViewGroup linearLayout = findViewById(R.id.mapLayout);

                View cell = new View(MainActivity.this);

                GradientDrawable shape = new GradientDrawable();

                shape.setShape(GradientDrawable.RECTANGLE);

                //shape.setColor(Color.rgb(33,150,243));

                if (shiftMap.getOra00() ==1)
                {
                    shape.setColor(Color.rgb(33,150,243));
                }
                else if (shiftMap.getOra00() ==0.5)
                {
                    shape.setColor(Color.rgb(179,229,252));
                }
                else if (shiftMap.getOra00() ==0)
                {
                    shape.setColor(Color.rgb(255,255,255));
                }

                shape.setStroke(3, Color.rgb(255,255,255));

                shape.setCornerRadius(5);

                LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(ViewGroup.LayoutParams.MATCH_PARENT, ViewGroup.LayoutParams.MATCH_PARENT);

                lp.setMargins(1, 1, 1, 1);

                cell.setLayoutParams(lp);

                cell.setBackground(shape);

                linearLayout.addView(cell);
                Log.i("Operator",  shiftMap.getOperator() + " | " + shiftMap.getOra00() + " | " + shiftMap.getOra01() + " | " + shiftMap.getOra02());
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {}
    };

知道我在做什么错吗？

Answer 1

我的代码存在的问题是，每次更新数据库时，它都会在UI中创建新控件。我设法通过删除每个控件然后更新UI来解决此问题，一切都很好。代码下方：

ValueEventListener eventListener = new ValueEventListener() {
        @Override
        public void onDataChange(DataSnapshot dataSnapshot) {
            ViewGroup linearLayout = findViewById(R.id.mapLayout);

            if(linearLayout.getChildCount() > 0)
                linearLayout.removeAllViews();

            for(DataSnapshot ds : dataSnapshot.getChildren()) {

                MapModel shiftMap = ds.getValue(MapModel.class);

                View cell = new View(MainActivity.this);

                GradientDrawable shape = new GradientDrawable();

                shape.setShape(GradientDrawable.RECTANGLE);

                //shape.setColor(Color.rgb(33,150,243));

                if (shiftMap.getOra00() == 1)
                {
                    shape.setColor(Color.rgb(33,150,243));
                }
                else if (shiftMap.getOra00() ==0.5)
                {
                    shape.setColor(Color.rgb(179,229,252));
                }
                else if (shiftMap.getOra00() ==0)
                {
                    shape.setColor(Color.rgb(255,255,255));
                }

                shape.setStroke(3, Color.rgb(255,255,255));

                shape.setCornerRadius(5);

                LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(70, 50);

                lp.setMargins(1, 1, 1, 1);

                cell.setLayoutParams(lp);

                cell.setBackground(shape);

                linearLayout.addView(cell);
                Log.i("Operator",  shiftMap.getOperator() + " | " + shiftMap.getOra00() + " | " + shiftMap.getOra01());
            }
        }

        @Override
        public void onCancelled(DatabaseError databaseError) {}
    };

代码：

ViewGroup linearLayout = findViewById(R.id.mapLayout);

            if(linearLayout.getChildCount() > 0)
                linearLayout.removeAllViews();

删除线性布局中的每个控件。

发生数据库更改后更新Ui

1 个答案: