如何在回收器视图的 onBindViewHolder() 方法中调用 getString()？

Question

Context

I am creating a RecyclerAdapter to display the forecast info on a certain day. My RecyclerView contains multiple days, each of which is modified with the onBindViewHolder.

The layout of each day has 3 text views. The first one contains a string that is the summary. The second one contains a string with a double as a positional argument which represents the low temperature. The third is identical to the second, but represents the high temperature.

Below is the code of my onBindViewHolder method:

@Override
public void onBindViewHolder(@NonNull DailyForecastAdapter.ViewHolder viewHolder, int i) {

    Datum datum = forecast.get(i);

    TextView summary = viewHolder.summaryTextView;
    TextView tempHigh = viewHolder.tempHighTextView;
    TextView tempLow = viewHolder.tempLowTextView;

    summary.setText(datum.getSummary());
    tempHigh.setText(datum.getTemperatureHigh());
    tempLow.setText(datum.getTemperatureLow());
}

Issue

Since high and low temperatures are doubles , I need to format the string accordingly, lest I overwrite the string with just a double value. Here are the string resources for high temperature and low temperature:

<string name="temperature_high">High of %1$.2f</string>
<string name="temperature_low">Low of %1$.2f</string>

Outside of the RecyclerAdapter class I know how to do this, below is an example of how I format a string inside a Fragment:

 String moddedString = String.format(getString(R.string.temperature), temp);
 ((TextView)activity.findViewById(R.id.temperatureDisplay)).setText(moddedString);

However, I don't have access to the getString() function inside the RecyclerAdapter , so I cannot format the string appropriately to insert the temperature I need without completely overriding the String with a double.

Question

How do I use getString() inside the onBindViewHolder() method?

Answer 1

How do I use getString() inside the onBindViewHolder() method?

Every ViewHolder instance has an itemView field, which is an instance of View . Every View instance has a getContext() method; you can use this to access resources.

String text = viewHolder.itemView.getContext().getString(R.string.mystring);

Answer 2

您可以使用上下文获取字符串资源。

  context.getString(R.string.temperature)

Answer 3

You can save a local copy of Context with the constructor of your RecyclerViewAdapter class:

public class YourRecyclerViewAdapter extends RecyclerView.Adapter<YourRecyclerViewAdapter.ViewHolder> {


    private Context context;


    public YourRecyclerViewAdapter(Context context) {
        this.context = context;
    }


    @Override
    public void onBindViewHolder(@NonNull final ViewHolder holder, final int position) {
        String string = context.getString(R.string.your_string);
    }

Answer 4

//1. Get context from adapter constructor:
public YourRecyclerViewAdapter(Context context) 


//2. As @Ben P.said, get context from item view:
Context context = viewHolder.itemView.getContext();


//3. I think the adapter only binds the data to the view 
//and doesn’t care about the logic, so maybe you can 
//prepare the data before passing it to the adapter
CustomData {
    private String temperature;
    public String getTemperature() {
          return temperature;
    }
}
    
//Then pass the data to adapter by construtor:
YourRecyclerViewAdapter adapter = new YourRecyclerViewAdapter(data);

//Or update data by adapter functions:
adapter.updateData(data);