When I use WeakReference, cannot resolve symbol message on android

Question

My app camera preview record app. I use ArrayList, during record camera preview.

ArrayList declared on global variable

private ArrayList<OutputInputPair> pairs = new ArrayList<OutputInput>();

and when I record stop button click, execute stop() method

@Override
public void stop() {
   pairs.clear();
   pairs = null;
   stopped = true;
}

so, If I continue recording without click record stop button. occur a lot of memory leak.

so, I want use WeakReference I try this

//private ArrayList<OutputInputPair> pairs = new ArrayList<OutputInputPair();
  private ArrayList<WeakReference<OutputInputPair>> pairs = new ArrayList<WeakReference<OutputInputPair>>();  //global variable

 @Override
 public void add(OutputInputPair pair) {
    //pairs.add(pair);
    pairs.add(new WeakReference<OutputInputPair>(pair));
 }

 @Override
 public void stop() {
    pairs.clear();
    pairs = null;
    stopped = true;
 }

 @Override
 public void process() {  //record method
    //for (OutputInputPair pair : pairs) {
    for (WeakReference<OutputInputPair> pair = pairs) {
        pair.output.fillCommandQueues(); //output is cannot resolve symbol message 
        pair.input.fillCommandQueues(); //input is cannot resolve symbol message
    }

    while (!stopped) { //when user click stop button, stopped = true.
        //for (OutputInputPair pair : pairs) {
         for (WeakReference<OutputInputPair> pair : pairs) {
             recording(pair); //start recording 
         }
     }
   }

public interface IOutputRaw  {   //IInputRaw class same code.
    void fillCommandQueues(); 
}

I think How to avoid memory rick, use WeakReference is right?

How to fix cannot resolve symbol message use weakreference?

thanks.

public class OutputInputPair {
    public IOutputRaw output;
    public IInputRaw input;

     public OutputInputPair(IOutputRaw output, IInputRaw input) {
         this.output = output;
         this.input = input;
     }
 }

Answer 1

I don't know much of WeakReference. But you should use the get() method to get the actual reference.

Use:

if(pair == null) continue;
OutputInputPair actualPair = pair.get();
if(actualPair == null) continue;
actualPair.output.fillCommandQueues();
actualPair.input.fillCommandQueues();

instead of:

pair.output.fillCommandQueues();
pair.input.fillCommandQueues();