How to send key event to an edit text

问题

For example, send a backspace key to the edit text control to remove a character or send a char code like 112 to append a character in the edittext control programmatically.

Actually, I need a method like

void onKeyReceived(int keyCode)
{
  // here I would like to append the keyCode to EditText, I know how to add a visible character, but what about some special keys, like arrow key, backspace key.
}

回答1:

To send a simulated backspace key press to an EditText you have to send both key press and release events. Like this:

mEditText.dispatchKeyEvent(new KeyEvent(0, 0, KeyEvent.ACTION_DOWN,
    KeyEvent.KEYCODE_DEL, 0));
mEditText.dispatchKeyEvent(new KeyEvent(0, 0, KeyEvent.ACTION_UP,
    KeyEvent.KEYCODE_DEL, 0));

This can be used to send any other key code, not just delete.

回答2:

Your question is not all that clear, but I think you want to modify/append text to a TextView when certain buttons are pressed. If so, you want a combination of some of the existing answers.

@Override
public void onCreate(Bundle savedInstanceState) {
    ...
    (TextView) textView = (TextView) findViewById(R.id.myTextView);
}

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
    switch(keyCode) {
    case KeyEvent.KEYCODE_BACK:
        // user pressed the "BACK" key.  Append "_back" to the text
        textView.append("_back");
        return true;
    case KeyEvent.KEYCODE_DEL:
        // user pressed the "BACKSPACE" key.  Append "_del" to the text
        textView.append("_del");
        return true;
    default:
        return super.onKeyDown(keyCode, event);
    }
}

Whether to return true for each case you have handled (as above) or to always return super.onKeyDown(keyCode, event); after your switch statement will depend on your exact requirements. Check the documentation for the behaviour of onKeyDown

If, instead of appending text in each case you want to delete a character, or move the cursor, you could do that in each case statement. Have a look at the TextView documentation for the different methods you can call. Also look at the KeyEvent documentation for a list of the keys you can check for.

回答3:

I think you need use addTextChangedListener to EditText.
Refer the answer of EditText input with pattern android and Live editing of users input

回答4:

virsir , I suppose you are looking for dispatching hard keys programmatically.

For that you may try dispatch (KeyEvent.Callback receiver, KeyEvent.DispatcherState state, Object target) with an example at Back and other hard keys: three stories

Hope that helps.

回答5:

Check for key events in your activity. for example, this code listens for back keypress:

@Override
public boolean onKeyDown(int keyCode, KeyEvent event)
{
    if ((keyCode == KeyEvent.KEYCODE_BACK))
    {
    finish();
    }
    return super.onKeyDown(keyCode, event);
}

回答6:

just use the setText method to do this. If you are wanting to simulate a backspace you could do something like this.

String curText = mEditText.getText();
if(!curText.equals("")){
    mEditText.setText(curText.subString(0, curText.length - 1));
}

回答7:

to simulate backspace key, just ad code

editText.setText(editText.getText().substring(0,editText.getText().length()-1))
getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);

to simulate adding a character, put the code

editText.setText(editText.getText() + (char) charCode)

getWindow().setSoftInputMode(WindowManager.LayoutParams.SOFT_INPUT_STATE_VISIBLE);

回答8:

Take a look at this article: creating-input-method.html. Basically, you can either manually send KeyEvents or you can manually edit and commit text around the cursor in the application's Input View.These are all done via your IME's InputConnection.

Hope this helps,

回答9:

if you want a click listener, the best way to do it is this:

View textfield = findViewById(R.id.textfield);  
textfield .setOnClickListener(new View.OnClickListener() { 
public void onClick(View v) {  
/*your code for the click event here*/ }});

if you want a backspace button, do this:

public void backSpace() {   
EditText textfield = (EditText)findViewById(R.id.textfield);  
    try {  
        textfield.getText().delete(textfield.getSelectionEnd() - 1, textfield.getSelectionStart());  
    } catch (Exception e) {  
        try {  
            textfield.getText().delete(textfield.length() - 1, textfield.length());  
        } catch (Exception myException) {  
        //textfield.getText().delete(textfield.length(), textfield.length() - 1);  
        }  
    }  
}

if you want to append a character in the EditText, do this:

EditText textfield = (EditText)findViewById(R.id.textfield);  
textfield.setText(textfield.getText().concat("112"));

回答10:

try implementing TextWatcher interface.

it has 3 methods which you need to override.

public void afterTextChanged(Editable s) {

    Log.v("afterTextChanged","here");
}
public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    Log.v("beforeTextChanged","here");
}

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

I think this will work.

来源：https://stackoverflow.com/questions/4779000/how-to-send-key-event-to-an-edit-text

标签

java

android

android-edittext