android - 如何以 android auntomatica 方式获取文本框的内容？无需用户干预

Question

我正在 android 中开发一个应用程序，并想开发一种方法来捕获您在框中键入的文本，但不希望用户按下任何按钮，但是在文本写在框上的那一刻，采取几秒钟后获得文本，然后将其与其他文本进行比较。

Answer 1

您可以使用EditText.addTextChangedListener()方法来侦听 EditText 文本更改。

您可以检查此示例实现：

editText = (EditText) findViewById(R.id.edit_text);
editText.addTextChangedListener(new TextWatcher(){
    @Override
    public void onTextChanged(CharSequence s, int start, int before, int count) {
        String text = s.toString();
    }

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

    @Override
    public void afterTextChanged(Editable s) {
    }
}

Answer 2

如果将 onTextChangedListener 添加到 EditText，它将如下所示：

textMessage = (EditText)findViewById(R.id.textMessage);
textMessage.addTextChangedListener(new TextWatcher(){
    public void afterTextChanged(Editable s) {
        String text = txtMessage.getText().toString();
    }
    public void beforeTextChanged(CharSequence s, int start, int count, int after){}
    public void onTextChanged(CharSequence s, int start, int before, int count){}
}); 

Answer 3

TextWatcher您可以向您添加一个EditText并创建一个异步任务并将其发送到睡眠所需的时间，然后使用来自EditText. 如果在任务仍在运行时文本中有任何更改，则取消任务并开始一个新任务，如下所示：

private UpdateFilterTask currentFilterTask = null;

private class UpdateFilterTask extends AsyncTask {

    private String mInputText;

    public UpdateFilterTask(String inputText){
        this.mInputText = inputText;
    }

    @Override
    protected Object doInBackground(Object[] params) {
        try {
            // Set the desired amount of time to wait in here, right now is 5 secs
            Thread.sleep(5000);
        } catch (InterruptedException e) {
            return false;
        }

        if(this.isCancelled()){
            return false;
        }

        return true;
    }

    @Override
    protected void onPostExecute(Object o) {
        Boolean didFinish = (Boolean) o;
        if(didFinish){
            // Do whatever you like with the mInputText
        }
    }
}

private class SearchTextWatcher implements TextWatcher {
    @Override public void beforeTextChanged(CharSequence s, int start, int count, int after) {}
    @Override public void afterTextChanged(Editable s) {}
    @Override
    public void onTextChanged(final CharSequence s, int start, int before, int count) {
        if(currentFilterTask != null){
            // If there was a running task previously, interrupt it
            currentFilterTask.cancel(true);
            currentFilterTask = null;
        }

        if(s.toString().trim().isEmpty()){
            // Return to the original state as the EditText is empty now
            return;
        }

        currentFilterTask = new UpdateFilterTask(s.toString());
        currentFilterTask.execute();
    }
}