Android 以编程方式添加带有 ConstraintLayout 的 ImageView

Question

我想使用 ConstraintLayout 以编程方式将多个 ImageView 插入到 RecyclerView 中。

要使用水平偏差以等距方式插入图像，每个图像的值计算如下:

float biasedValue = (1f / (flightPlanWeather.weather.size () + 1f)) * (i + 1f);

代码如下

public class FlightPlanWeatherRecyclerAdapter extends RecyclerView.Adapter<FlightPlanWeatherRecyclerAdapter.MyViewHolder> {
    private static final String TAG = FlightPlanWeatherRecyclerAdapter.class.getName();
    private List<FlightPlanWeather> dataSet;
    private LayoutInflater mInflater;
    Context mContext;


    // Provide a suitable constructor (depends on the kind of dataset)
    // data is passed into the constructor
    public FlightPlanWeatherRecyclerAdapter(Context context, List<FlightPlanWeather> data) {
        this.mInflater = LayoutInflater.from(context);
        this.dataSet = data;
        this.mContext = context;
    }

    // inflates the row layout from xml when needed
    @Override
    public MyViewHolder onCreateViewHolder(ViewGroup parent, int viewType) {
        View view = mInflater.inflate(R.layout.row_item_flightplan_weather, parent, false);
        return new MyViewHolder(view);
    }


    @Override
    public void onBindViewHolder(MyViewHolder holder, int position) {
        holder.bind(dataSet.get(position));
        FlightPlanWeather flightPlanWeather = dataSet.get(position);

        holder.from_img.setImageResource(flightPlanWeather.from.getImg_resource());
        holder.from_label.setText(flightPlanWeather.from.getLabel());

        holder.to_img.setImageResource(flightPlanWeather.to.getImg_resource());
        holder.to_label.setText(flightPlanWeather.to.getLabel());


        int dimensionInPixel = 256;

        ConstraintLayout.LayoutParams lp =
                new ConstraintLayout.LayoutParams(/*ConstraintLayout.LayoutParams.WRAP_CONTENT,*/ dimensionInPixel,
                        /*ConstraintLayout.LayoutParams.WRAP_CONTENT*/ dimensionInPixel);



        //weather
        for(int i=0; i<flightPlanWeather.weather.size(); i++ ){
            ConstraintSet constraintSet = new ConstraintSet();

            holder.mConstraintSetList.add(constraintSet);
            ImageView imageView = new ImageView(mContext);
            imageView.setId(View.generateViewId());
            imageView.setImageResource(flightPlanWeather.weather.get( i ));
            imageView.setLayoutParams(lp);
            imageView.requestLayout();
            holder.weather.add(imageView);
            holder.mConstraintLayout.addView( imageView/*, lp */);

            //}
            constraintSet.clone(holder.mConstraintLayout);

            float biasedValue = (1f/ (flightPlanWeather.weather.size()+1f)) * (i+1f);
            Log.d(TAG, Float.toString( biasedValue ) +"i:"+ Integer.toString( i )+"size:"+ flightPlanWeather.weather.size());
            constraintSet.setHorizontalBias(imageView.getId(), biasedValue);
            constraintSet.connect(imageView.getId(), ConstraintSet.START, holder.mConstraintLayout.getId(), ConstraintSet.START, 0);
            constraintSet.connect(imageView.getId(), ConstraintSet.END, holder.mConstraintLayout.getId(), ConstraintSet.END, 0);
            constraintSet.connect(imageView.getId(), ConstraintSet.TOP, holder.mConstraintLayout.getId(), ConstraintSet.TOP, 0);
            constraintSet.connect(imageView.getId(), ConstraintSet.BOTTOM, holder.mConstraintLayout.getId(), ConstraintSet.BOTTOM, 0);
            constraintSet.applyTo(holder.mConstraintLayout);
            holder.mConstraintLayout.requestLayout();
        }

    }

    // Return the size of your dataset (invoked by the layout manager)
    @Override
    public int getItemCount() {
        return dataSet == null ? 0 : dataSet.size();
    }


    // Provide a reference to the views for each data item
    // Complex data items may need more than one view per item, and
    // you provide access to all the views for a data item in a view holder
    // Static inner class to initialize the views of rows
    static class MyViewHolder extends RecyclerView.ViewHolder implements View.OnClickListener{

        TextView from_label;
        TextView to_label;
        ImageView from_img;
        ImageView to_img;
        ImageView line;
        ConstraintLayout mConstraintLayout;

        List<ConstraintSet> mConstraintSetList = new ArrayList<>(  );
        List<ImageView> weather = new ArrayList<>(  );

        public MyViewHolder(View itemView) {
            super(itemView);
            itemView.setOnClickListener(this);

            mConstraintLayout  = (ConstraintLayout) itemView.findViewById(R.id.mainConstraintLayout);
            from_label = (TextView) itemView.findViewById(R.id.from_label);
            to_label = (TextView) itemView.findViewById(R.id.to_label);
            from_img = (ImageView) itemView.findViewById(R.id.from_img);
            to_img = (ImageView) itemView.findViewById(R.id.to_img);
            line = (ImageView) itemView.findViewById(R.id.line);



        }

        public void bind(Object object){


        }

        @Override
        public void onClick(View view) {
            Log.d("onclick", "onClick " + getLayoutPosition() + " " /*+ /*item.getText()*/);
        }
    }

}

问题是天气的水平偏差无法正常工作 screenshot

View 应该是这样的: screenshot

Answer 1

问题在于您正在为每个 View 重用布局参数。由于布局参​​数托管布局信息，因此您创建并设置布局信息的每个新 ImageView 都会清除先前的布局信息。

为每个ImageView创建一组新的布局参数，它应该可以正常工作。将以下内容移至循环中:

ConstraintLayout.LayoutParams lp =
                new ConstraintLayout.LayoutParams(/*ConstraintLayout.LayoutParams.WRAP_CONTENT,*/ dimensionInPixel,
                        /*ConstraintLayout.LayoutParams.WRAP_CONTENT*/ dimensionInPixel);