在Android上处理程序时感到困惑

Question

I'm trying to send a String[] to a thread in an inner class of another class(if that makes sense). Then i want To do some work with the String[] then Output it back to the UI. But im not sure about how to do that? I also what to use messages so i can control what is going to be exeucted in the UI.

Heres my MainActivity :

public class MainActivity extends Activity implements OnClickListener {
EditText cl;
TextView info;
Button enter;
Button line;
Button arc;
Line callLine = new DrawingUtils.Line();
Enter callEnter = new DrawingUtils.Enter();
Arc callArc = new DrawingUtils.Arc();

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    info = (TextView) findViewById(R.id.info);
    enter = (Button) findViewById(R.id.enter);
    line = (Button) findViewById(R.id.line);
    arc = (Button) findViewById(R.id.arc);
    cl = (EditText) findViewById(R.id.editText1);

    Handler uiHandler = new Handler() {
        public void handleMessage(Message msg) {
            switch (msg.what) {

            }
        }
    };

}

@Override
public void onClick(View v) {
    switch (v.getId()) {
    case R.id.enter:
        String in = cl.getText().toString();
        String[] Input = in.split(",");
        // I would like to send Input[] to the line Thread in DrawingUtils
        callEnter.start();
        break;
    case R.id.line:
        callLine.start();
        break;
    case R.id.arc:
        callArc.start();
        break;

    }

};

}

Heres the other class that has the in class with the Thread :

public class DrawingUtils {

// Thread classes for buttons
public static class Line extends Thread {
    Thread line = new Thread() {
        public void run() {
            Looper.prepare();
            Handler lineHandler = new Handler() {
                public void handleMessage(Message msg) {
                    // How to get Input from Enter button to use in thread
                }
            };
            Looper.loop();
            // Then I need to do some work
            // Then Send the worked data back to the uiHandler in
            // oncreate().
        }
    };
}

i was using handlers cuase they seemed like thats what would work for my code. when someone clicks Line it will set a textview saying (INPUT POINT1) then the thread will wait and when the user inputs x,y,z to the edittext and click Enter the input will be put into a string then seperated by a comma and put into a string array which will be handle to the line thread then at the end of Enters code notifyAll() will be called to allow the line thread to continue and ask for the next input. at the end of the line thread it will be handled back to the UI thread

Answer 1

Why do you want to use Handlers? I would use an AsyncTask with parameters, they are perfect in most cases, like your. Look at: http://developer.android.com/reference/android/os/AsyncTask.html

I would try this ( MyAsyncTask is a subclass of your Activity class ):

private class MyAsyncTask extends AsyncTask<String[], Void, Boolean> {
    //declare here local variables
    @Override
    protected void onPreExecute() {
        super.onPreExecute();

        //prepare your local variables for the computation
    }

@Override
protected Boolean doInBackground(String[]... arg0) {

    String[] myStringArray = arg0[0];
    // make your manipulation of myStringArray

    return null; // return the result and set your local variable
}

    @Override
    protected void onPostExecute(Boolean result) {
        super.onPostExecute(result);

        //update ui using result and/or local variable
    }
}

From click event you call something like this:

String[] strings = {"1", "2", "3"};
new MyAsyncTask().execute(strings);

I want to alert you about your code:

@Override
public void onClick(View v) {
    switch (v.getId()) {
    case R.id.enter:
        String in = cl.getText().toString();
        String[] Input = in.split(",");
        // I would like to send Input[] to the line Thread in DrawingUtils
        callEnter.start();
        break;
    case R.id.line:
        callLine.start();
        break;
    case R.id.arc:
        callArc.start();
        break;
    }
};

the variable Input is initialized only in the first case, if the case statement select the R.id.line or R.id.arc you are in trouble...