开关-大小写表达式必须是常量表达式，我不能使用if-else语句

Question

This is a project of QR Code generation and this is the source of the code That is the source here an error of the constant case I know that it must put in If-else but I don't know how in this project anyone can help me ?!

//That is a QR code generator project`enter code here`
    @Override
    public void onClick(View v) {
        // TODO Auto-generated method stub
        switch (v.getId()) {
          case R.id.button1://<--- is the error .. I can't make it If-else statement
           EditText qrInput = (EditText) findViewById(R.id.QR);
           String qrInputText = qrInput.getText().toString();
           Log.v(LOG_TAG, qrInputText);

           //Find screen size
           WindowManager manager = (WindowManager) getSystemService(WINDOW_SERVICE);
           Display display = manager.getDefaultDisplay();
           Point point = new Point();
           display.getSize(point);
           int width = point.x;
           int height = point.y;
           int smallerDimension = width < height ? width : height;
           smallerDimension = smallerDimension * 3/4;

           //Encode with a QR Code image
           QREncoder qrCodeEncoder = new QREncoder(qrInputText, 
                     null, 
                     Contents.Type.TEXT,  
                     BarcodeFormat.QR_CODE.toString(), 
                     smallerDimension);
           try {
            Bitmap bitmap = qrCodeEncoder.encodeAsBitmap();
            ImageView myImage = (ImageView) findViewById(R.id.imageView1);
            myImage.setImageBitmap(bitmap);

           } catch (WriterException e) {
            e.printStackTrace();
           }


           break;

           // More buttons go here (if any) ...

          }
         }
    }

Answer 1

Take a look at the official blog post about this:

http://tools.android.com/recent/switchstatementconversion

http://tools.android.com/tips/non-constant-fields

Basically, resource constants in library projects are no longer "final". From the ADT Site:

In other words, the constants are not final in a library project. The reason for this is simple: When multiple library projects are combined, the actual values of the fields (which must be unique) could collide. Before ADT 14, all fields were final, so as a result, all libraries had to have all their resources and associated Java code recompiled along with the main project whenever they were used. This was bad for performance, since it made builds very slow. It also prevented distributing library projects that didn't include the source code, limiting the usage scope of library projects.

so if you the the fix it will convert switch into if and else...

int id = view.getId();
if (id == R.id.button1) {
    action1();
} else if (id == R.id.button2) {
    action2();
} else if (id == R.id.button3) {
    action3();
}