如何实现按钮单击事件中的图像和文本切换？

Question

I'm trying to implement a button click event to switch images in an image switcher along with updating textView strings on button click.So far I've got it working for the image,but when I tried to modify the method to include updating the strings I'm getting the following errors:

1. On the getMyString call I get the following:The method getMyString(int, Context) in the type AboutActivity is not applicable for the arguments (int)

2. At the method header of getMyString this: Multiple markers at this line

   • Syntax error on token "(", ; expected
   • Syntax error on token ")", ; expected

3. And where I'm calling the strings in the switch this: Void methods cannot return a value

   • Illegal modifier for parameter getMyString; only final is permitted

Does anyone know where I'm going wrong with this implementation?I thought it may have been missing braces or that the code was placed out of context,but from looking at the errors it seems to be the way in which I'm calling the getMyString() in the onClick event.

public class AboutActivity extends Activity implements OnClickListener{


    private ImageSwitcher imageSwitcher;
    Button btnNext;
    TextView tView;


    int imageIds[]=
    {R.drawable.mark1,R.drawable.mark2,R.drawable.mark3};
    int messageCount=imageIds.length;
    // to keep current Index of ImageID array
    int currentIndex=-1;

    private int clicks = 1;

    protected void onCreate(Bundle savedInstanceState) {
        // TODO Auto-generated method stub
        super.onCreate(savedInstanceState);
        setContentView(R.layout.about);

        final Intent intent1=new Intent(this,AboutActivity.class);
        final Intent intent2=new Intent(this,MainActivity.class);

        final ViewGroup actionBarLayout = (ViewGroup) getLayoutInflater().inflate(R.layout.a,null);

        // get The references
        btnNext=(Button)findViewById(R.id.buttonNext);
        imageSwitcher = (ImageSwitcher) findViewById(R.id.imageSwitcher1);
        tView = (TextView) findViewById(R.id.textView1);
        // Set the ViewFactory of the ImageSwitcher that will create ImageView object when asked
        imageSwitcher.setFactory(new ViewFactory() {
        public View makeView() {
        // TODO Auto-generated method stub
        // Create a new ImageView set it's properties
        ImageView imageView = new ImageView(getApplicationContext());
        imageView.setScaleType(ImageView.ScaleType.FIT_CENTER);
        imageView.setLayoutParams(new
        ImageSwitcher.LayoutParams(LayoutParams.FILL_PARENT,LayoutParams.FILL_PARENT));
        return imageView;
        }
        });

     // Declare the animations and initialize them
        Animation in = AnimationUtils.loadAnimation(this,android.R.anim.slide_in_left);
        Animation out = AnimationUtils.loadAnimation(this,android.R.anim.slide_out_right);
        // set the animation type to imageSwitcher
        imageSwitcher.setInAnimation(in);
        imageSwitcher.setOutAnimation(out);
        // ClickListener for NEXT button
        // When clicked on Button ImageSwitcher will switch between Images
        // The current Image will go OUT and next Image will come in with specified animation
        btnNext.setOnClickListener(new View.OnClickListener() {
        public void onClick(View v) {
        // TODO Auto-generated method stub
        currentIndex++;
        // If index reaches maximum reset it
        if(currentIndex==messageCount)
        currentIndex=0;
        imageSwitcher.setImageResource(imageIds[currentIndex]);
        tView.setText(getMyString(clicks++, v.getContext()));
        }

        });


        // Set up your ActionBar
        final ActionBar actionBar = getActionBar();
        actionBar.setDisplayShowHomeEnabled(false);
        actionBar.setDisplayShowTitleEnabled(false);
        actionBar.setDisplayShowCustomEnabled(true);
        actionBar.setCustomView(actionBarLayout);

        // You customization
        final int actionBarColor = getResources().getColor(R.color.action_bar);
        actionBar.setBackgroundDrawable(new ColorDrawable(actionBarColor));

        final Button actionBarHome = (Button) findViewById(R.id.action_bar_title);
        actionBarHome.setBackgroundResource(R.drawable.ic_action_back);
        actionBarHome.setOnClickListener(this);
        actionBarHome.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {                

               startActivity(intent2);

            }

        });

        final Button actionBarInfo = (Button) findViewById(R.id.action_bar_staff);
        actionBarInfo.setBackgroundResource(R.drawable.ic_action_help);
        actionBarInfo.setOnClickListener(this);
        actionBarInfo.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {                

               startActivity(intent1);

            }

        });


    }

    //method called to update textview strings.
    public String getMyString(int variable, Context applicationContext){
        switch(variable){
            case 1:
                return applicationContext.getResources().getString(R.string.cutString);
                break;
            case 2:
                return applicationContext.getResources().getString(R.string.markString);
                break;
            case 3:
                return applicationContext.getResources().getString(R.string.measureString);
                break;
        }

    }


    @Override
    public void onClick(View arg0) {
        // TODO Auto-generated method stub

    }


}

Answer 1

1.On the getMyString call I get the following:The method getMyString(int, Context) in the type AboutActivity is not applicable for the arguments (int)

You have

 tView.setText(getMyString(clicks++));

only passing it an int as the error says but them method takes (int, Context) . So it should be

 tView.setText(getMyString(clicks++, v.getContext()));

So that you are passing it the correct params that the method takes.

2At the method header of getMyString this: Multiple markers at this line - Syntax error on token "(", ; expected - Syntax error on token ")", ; expected

It looks like your getMyString() method is inside onCreate() or some other method. Move it outside of any method.

3.And where I'm calling the strings in the switch this: Void methods cannot return a value - Illegal modifier for parameter getMyString; only final is permitted

I think this is also due to your method being inside of another method but the way its set up its a little confusing what's going on. Make these changes and run again and see what errors you get.

Edit

You need to have the method return a String and right now it won't return one if none of the cases are true . Therefore, you can have a final . Therefore, you can have a final return where you return a default String` value in case non of them match. Or you can do something like this

/method called to update textview strings.
public String getMyString(int variable, Context applicationContext){
    String text = "";  // create a String variable to return and give it whatever 
                       // value you want in case none of the cases return true
    switch(variable){  // assign the variable below
        case 1:
            text = applicationContext.getResources().getString(R.string.cutString);
            break;
        case 2:
            text = applicationContext.getResources().getString(R.string.markString);
            break;
        case 3:
            text = applicationContext.getResources().getString(R.string.measureString);
            break;
    }
  return text; //just one return

}

Answer 2

I think one error is the following: in the onClick() function, you call the getMyString function with the integer clicks as the only input parameter, while in the definition of the getMyString function, you say that the function has to receive an integer AND the applicationContext. I would suggest to make the call of the getMyString function like this:

 tView.setText(getMyString(clicks++, getApplicationContext()));

Answer 3

On the getMyString call I get the following:The method getMyString(int, Context) in the type AboutActivity is not applicable for the arguments (int)

Becasuse you don't have a method which only gets an integer as a parameter. Your method get 2 paramters:

String getMyString(int variable, Context applicationContext)

Anyway solution; change this:

tView.setText(getMyString(clicks++));

To this:

tView.setText(getMyString(clicks++), v.getContext());