How to set Min text (Mandatory) and Max text in EditText

问题

In my EditText field, I want to give some min text as mandatory and max text as the limit, is there any way to achieve that?

If one is to type text, the numeric count has to decrease. How would I do that?

<EditText
    android:id="@+id/editText1"
    android:layout_width="wrap_content"
    android:layout_height="wrap_content"
    android:layout_alignParentLeft="true"
    android:layout_below="@+id/textView1"
    android:layout_marginTop="24dp"
    android:maxLength="175"
    android:ems="10" />

this is my adding activity.java

@Override
public void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.home_layout);
    System.out.println(PRAYER_CATEGORY.length);
    tvPrayer = (TextView) findViewById(R.id.mystate);
    spinnerPrayers = (Spinner) findViewById(R.id.spinnerstate);

    ArrayAdapter<String> adapter_state = new ArrayAdapter<String>(this,
            android.R.layout.simple_spinner_item, PRAYER_CATEGORY);
    adapter_state
            .setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    spinnerPrayers.setAdapter(adapter_state);

    value=(EditText)findViewById(R.id.editText1);
    value
       .setOnFocusChangeListener(new View.OnFocusChangeListener() {
            @Override
            public void onFocusChange(View v, boolean hasFocus) {
                if (hasFocus) {
                    if (value.getText().toString().trim()
                            .length() < 3) {

                        value.setError("Failed");
                    } else {
                        value.setError(null);
                    }
                }
                else {
                    if (value.getText().toString().trim()
                            .length() < 3) {
                        value.setError("Failed");
                    } else {
                            value.setError(null);
                    }
                }
            }
        });
        btnSpeakprayer = (ImageButton) findViewById(R.id.btnSpeakprayer);
        btn=(Button)findViewById(R.id.button1);
        pb=(ProgressBar)findViewById(R.id.progressBar1);
        pb.setVisibility(View.GONE);
        btn.setOnClickListener(this);

回答1:

Change your code TO this:

instead of value.getText().trim().length() try using value.getText().length()<3

value.setOnFocusChangeListener(new View.OnFocusChangeListener() {
    @Override
    public void onFocusChange(View v, boolean hasFocus) {
        if (hasFocus) {
            if (value.getText().toString().trim().length() < 3)
                value.setError("Failed");
            else
                value.setError(null);
        }
    }
});

回答2:

You can try this code

First of all you set your maxlength in xml file like this

                    <EditText
                    android:id="@+id/editText"
                    android:layout_width="match_parent"
                    android:inputType="textPassword"
                    android:lines="1"
                    android:maxLength="15"
                    android:maxLines="1"
                    android:singleLine="true" />

Then in your code you can write like this

et_billamt.setOnFocusChangeListener(new View.OnFocusChangeListener() {
        @Override
        public void onFocusChange(View v, boolean hasFocus) {
            if (hasFocus) {
                if (et_billamt.getText().toString().trim().length() < 5) {
                    et_billamt.setError("Failed");
                } else {
                    // your code here
                    et_billamt.setError(null);
                }
            } else {
                if (et_billamt.getText().toString().trim().length() < 5) {
                    et_billamt.setError("Failed");
                } else {
                    // your code here
                    et_billamt.setError(null);
                }
            }

        }
    });

I designed if after no focus, so here you can write for min length condition and max length condition

回答3:

Try this

EditText value =(EditText) findviewbyId(R.id.urEditTextId);// this line must be oncreate

// place these line where u want to check

String ed1=value .getText().toString();
int size=ed1.length();

you can match the digit and perform appropriate action

if(size==0)
//Toast : kindly enter atleast one letter 

if(size>175)
//Toast : max length 175 char 

回答4:

you can extend the EditText class, and override the onTextChanged method to monitor the text length change by yourself. Then you can control the limitation.

public class CustomEditText extends EditText{

public CustomEditText(Context context) {
    super(context);
    // TODO Auto-generated constructor stub
}

@Override
protected void onTextChanged(CharSequence text, int start,
        int lengthBefore, int lengthAfter) {
    // TODO Auto-generated method stub
    Log.i("length", "input text length = " + text.length());
    super.onTextChanged(text, start, lengthBefore, lengthAfter);
}

}

回答5:

Here's an EditText and a Button:

EditText myEditText;
Button button;

In your onCreate():

myEditText = (EditText) findViewById(R.id.edittext);
button = (Button) findViewById(R.id.button);

Say you submit or use the value that a user types in the myEditText using the button. Set an 'OnClickListener' to this button:

button.setOnClickListener(new OnClickListener() {
    public void onClick(View v) {
        if (mEditText.length() < 1 ||
            mEditText.length() > 175) {

               mEditText.setError("Value should be between 1 and 175 characters in length");

               mEditText.requestFocus();
        } else {

            // Value is valid (between 1 and 175 characters long)

               String text = mEditText.getText().toString();

            // submit
        } 
    }
});

来源：https://stackoverflow.com/questions/17781553/how-to-set-min-text-mandatory-and-max-text-in-edittext