Put constant text inside EditText which should be

Question

I want to have constant text inside editText like:

http://<here_user_can_write>

User should not be able to delete any chars from "http://", I searched about this and found this:

editText.setFilters(new InputFilter[] {
    new InputFilter() {
        public CharSequence filter(CharSequence src, int start,
            int end, Spanned dst, int dstart, int dend) {
            return src.length() < 1 ? dst.subSequence(dstart, dend) : "";
        }
    }
}); 

but I don't know whether it restricts user to not delete any chars from start to end limit. I also could not understand use of Spanned class.

One way would be a good choice if we can put a TextView inside EditText but I don't think it is possible in Android since both are Views, is it possible?

Answer 1

    EditText msg=new EditText(getContext());
                msg.setSingleLine(true);
                msg.setSingleLine();
                msg.setId(View.generateViewId());
                msg.measure(0,0);



                TextView count=new TextView(getContext());
                count.setTextColor(Color.parseColor("#666666"));
                count.setText("20");
                count.setPadding(0,0,(int)Abstract.getDIP(getContext(),10),0);
                count.measure(0,0);
float tenPIX =TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_DIP,10,getContext().getResources().getDisplayMetrics());

 msg.setPadding((int)tenPIX,(int)tenPIX,(int)(int)tenPIX+count.getMeasuredWidth(),(int)tenPIX);


                RelativeLayout ll1=new RelativeLayout(getContext());
                ll1.addView(msg,new LayoutParams(LayoutParams.MATCH_PARENT, LayoutParams.WRAP_CONTENT));

LayoutParams countlp=new LayoutParams(LayoutParams.WRAP_CONTENT, LayoutParams.WRAP_CONTENT);
                countlp.addRule(RelativeLayout.ALIGN_END,msg.getId());
                countlp.addRule(RelativeLayout.ALIGN_BASELINE,msg.getId());
                ll1.addView(count,countlp);

Answer 2

Taken from Ali Muzaffar's blog, see the original post for more details.

Use custom EditText View to draw the prefix text and add padding according to the prefix text size:

public class PrefixEditText extends EditText {

private String mPrefix = "$"; // add your prefix here for example $
private Rect mPrefixRect = new Rect(); // actual prefix size

public PrefixEditText(Context context, AttributeSet attrs) {
    super(context, attrs);
}

@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
    getPaint().getTextBounds(mPrefix, 0, mPrefix.length(), mPrefixRect);
    mPrefixRect.right += getPaint().measureText(" "); // add some offset

    super.onMeasure(widthMeasureSpec, heightMeasureSpec);
}

@Override
protected void onDraw(Canvas canvas) {
    super.onDraw(canvas);
    canvas.drawText(mPrefix, super.getCompoundPaddingLeft(), getBaseline(), getPaint());
}

@Override
public int getCompoundPaddingLeft() {
    return super.getCompoundPaddingLeft() + mPrefixRect.width();
}
}

Answer 3

This one is basically to add prefix "+91" to your edit text field of phone number.

1.Add this code to oncreate() of activity

@Override
    protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_sign_up);

   // Write other things......//

   etPhoneNumber.setFilters(new InputFilter[]{getPhoneFilter(),newInputFilter.LengthFilter(13)});

    etPhoneNumber.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            if (hasFocus) {
                if (etPhoneNumber.getText().toString().isEmpty()) {
                    etPhoneNumber.setText("+91");
                    Selection.setSelection(etPhoneNumber.getText(), etPhoneNumber.getText().length());                    }
            } else {
                if (etPhoneNumber.getText().toString().equalsIgnoreCase("+91")) {
                    etPhoneNumber.setFilters(new InputFilter[]{});
                    etPhoneNumber.setText("");
                    etPhoneNumber.setFilters(new InputFilter[]{getPhoneFilter(),new InputFilter.LengthFilter(13)});

                }
            }
        }
    });
}

2.Declare a method called getPhoneFilter()

    private InputFilter getPhoneFilter() {

    Selection.setSelection(etPhoneNumber.getText(), etPhoneNumber.getText().length());

    etPhoneNumber.addTextChangedListener(new TextWatcher() {

        @Override
        public void onTextChanged(CharSequence s, int start, int before, int count) {
        }

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                                      int after) {
        }

        @Override
        public void afterTextChanged(Editable s) {
            if(!s.toString().startsWith("+91")){
                if (etPhoneNumber.getFilters() != null && etPhoneNumber.getFilters().length > 0) {
                    etPhoneNumber.setText("+91");
                    Selection.setSelection(etPhoneNumber.getText(), etPhoneNumber.getText().length());
                }
            }
        }
    });

     // Input filter to restrict user to enter only digits..
    InputFilter filter = new InputFilter() {

        public CharSequence filter(CharSequence source, int start, int end,
                                   Spanned dest, int dstart, int dend) {

            for (int i = start; i < end; i++) {

                if (!String.valueOf(getString(R.string.digits_number)).contains(String.valueOf(source.charAt(i)))) {
                    return "";
                }
            }
            return null;
        }
    };
    return filter;
}

3.declare "digits_number" in your values file

    <string name="digits_number">1234567890+</string>

Answer 4

You had it almost right, try

private final String PREFIX="http://";

editText.setFilters(new InputFilter[]{new InputFilter() {
            @Override
            public CharSequence filter(CharSequence source, int start, int end, Spanned dest, int dstart, int
                    dend) {
                return dstart<PREFIX.length()?dest.subSequence(dstart,dend):null;
            }
        }});

Answer 5

CODE TO ADD CUSTOM PREFIX TO YOUR EDITTEXT (PREFIX NOT EDITABLE)

Code from Medium by Ali Muzaffar

public class PrefixEditText extends AppCompatEditText {
    float originalLeftPadding = -1;

    public PrefixEditText(Context context) {
        super(context);
    }

    public PrefixEditText(Context context, AttributeSet attrs) {
        super(context, attrs);
    }

    public PrefixEditText(Context context, AttributeSet attrs, int defStyleAttr) {
        super(context, attrs, defStyleAttr);
    }

    @Override
    protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
        super.onMeasure(widthMeasureSpec, heightMeasureSpec);
        calculatePrefix();
    }

    private void calculatePrefix() {
        if (originalLeftPadding == -1) {
            String prefix = (String) getTag();
            float[] widths = new float[prefix.length()];
            getPaint().getTextWidths(prefix, widths);
            float textWidth = 0;
            for (float w : widths) {
                textWidth += w;
            }
            originalLeftPadding = getCompoundPaddingLeft();
            setPadding((int) (textWidth + originalLeftPadding),
                getPaddingRight(), getPaddingTop(),
                getPaddingBottom());
        }
    }

    @Override
    protected void onDraw(Canvas canvas) {
        super.onDraw(canvas);
        String prefix = (String) getTag();
        canvas.drawText(prefix, originalLeftPadding, getLineBounds(0, null), getPaint());
    }
}

And XML

<com.yourClassPath.PrefixEditText
    android:layout_width="match_parent"
    android:layout_height="wrap_content"
    android:gravity="bottom"
    android:textSize="14sp"
    android:tag="€ " />

Answer 6

There was a slight problem with @Rajitha Siriwardena's answer. It assumes that the entire string except the suffix has been deleted before the suffix is meaning if you have the string

http://stackoverflow.com/

and try to delete any part of http:// you will delete stackoverflow.com/ resulting in only http://.

I also added a check incase the user tries to input before the prefix.

 @Override
 public void afterTextChanged(Editable s) {
     String prefix = "http://";
     if (!s.toString().startsWith(prefix)) {
         String cleanString;
         String deletedPrefix = prefix.substring(0, prefix.length() - 1);
         if (s.toString().startsWith(deletedPrefix)) {
             cleanString = s.toString().replaceAll(deletedPrefix, "");
         } else {
             cleanString = s.toString().replaceAll(prefix, "");
         }
         editText.setText(prefix + cleanString);
         editText.setSelection(prefix.length());
    }
}

Note: this doesn't handle the case where the user tries to edit the prefix itself only before and after.