Question

I need to do some validations sequentially and some of them involve complex database operations.

So, I need to do this in a separated thread of UI Thread, ok?
But some validations show messages to user, what need confirmation and
when user confirm, the next validation should be call.

This code example explains what I want to implement:

void makeValidation1(){

    if(condition1Valid()){
        makeValidation2();

    }else{
        DialogInterface.OnClickListener onClick = new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                makeValidation2();
            }
        };

        AlertDialog.Builder builder = new AlertDialog.Builder(this)
        .setMessage("really want to do this?")
        .setPositiveButton("Yes", onClick);

        builder.create().show();
    }
}

void makeValidation2(){

    if(condition2Valid()){
    }else{
        //...
    }
}

boolean condition1Valid() {
    // complex database Operations
    return false;
}
boolean condition2Valid() {
    //complex database Operations
    return false;
}

    //...


    void makeValidation9(){
         //...
    }

My question is: What the best way/pattern to implement this?

1 – Create one asyncTask for each validation? (I cant create only one AsyncTask, because confirmation messages can stop flux).

2 – Create a Runnable for each validation and create thread to run that when need call next validation?

3 – ???

---

edit
I tested this code @BinaryBazooka, but isnt work. Any help?

public class MainActivity extends Activity implements OnClickListener {

Thread mThread;
ProgressDialog mProgressDialog;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);

    Button button = new Button(this);
    button.setText("Start");
    setContentView(button, new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));
    button.setOnClickListener(this);

}

@Override
public void onClick(View v) {
    mThread = new Thread(new Runnable() {
        @Override
        public void run() {
            validations();
        }
    });

    AlertDialog.Builder builder = new AlertDialog.Builder(this);
    builder.setMessage("Start Thread?");
    builder.setPositiveButton("Ok", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialog, int which) {
            dialog.dismiss();

            mProgressDialog = new ProgressDialog(MainActivity.this);
            mProgressDialog.show();

            mThread.run();
        }
    });

    builder.create().show();
}

void validations(){
    //this method go on separated thread
    validation1();

    validation2();

    validation3();
}

void validation1(){

    if(true){
        final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

        builder.setMessage("Validation 1 failed. Go validation 2?");

        builder.setPositiveButton("Go", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
                mProgressDialog.show();
                //if user confirm, continue validation thread
                mThread.notify();
            }
        });
        builder.setOnCancelListener(new OnCancelListener() {

            @Override
            public void onCancel(DialogInterface dialog) {
                //if user cancel, stop validation thread
                mThread.interrupt();
            }
        });

        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mProgressDialog.hide();
                builder.create().show();
            }
        });

        try {
            synchronized (mThread) {
                //wait for user confirmation
                mThread.wait(); 
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }
}

private void validation2() {

    if(true){
        final AlertDialog.Builder builder = new AlertDialog.Builder(MainActivity.this);

        builder.setMessage("validacao 2 failed. Go validation 3?");
        builder.setPositiveButton("Go", new DialogInterface.OnClickListener() {
            @Override
            public void onClick(DialogInterface dialog, int which) {
                dialog.dismiss();
                mProgressDialog.show();
                mThread.notify();
            }
        });
        builder.setOnCancelListener(new OnCancelListener() {

            @Override
            public void onCancel(DialogInterface dialog) {
                mThread.interrupt();
            }
        });

        runOnUiThread(new Runnable() {
            @Override
            public void run() {
                mProgressDialog.hide();
                builder.create().show();
            }
        });

        try {
            synchronized (mThread) {
                mThread.wait();
            }
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
    }

}

private void validation3() {
    Log.i("TAG", "<<<<<<<<<<  >>>>>>>>>>>>");
    runOnUiThread(new Runnable() {
        @Override
        public void run() {
            Toast.makeText(MainActivity.this, "finished", Toast.LENGTH_SHORT);
        }
    });
}

}

Answer 1

I would create a new thread and sleep it during these dialog calls, you can access the UI directly from within your runnable with..

runOnUiThread(new Runnable() {                           

 public void run() {}

});

So something like..

Thread someThread = new Thread(new Runnable() { 

    @Override
    public void run(){
        runOnUiThread(new Runnable() {                           
            public void run() 
            {
                AlertDialog.Builder builder = new AlertDialog.Builder(context);                               
                builder.setMessage(R.string.msg);
                builder.setPositiveButton(R.string.btn_ok, new  DialogInterface.OnClickListener() {                 
                    @Override
                    public void onClick(DialogInterface dialog, int id) { 
                        dialog.dismiss();
                        someThread.notify();
                    }
                });
                AlertDialog alert = builder.create();       
                alert.show();
            }
        });
    }
    someThread.wait();