将edittext值设置为零(在为空时)，并在进行任何输入时将其删除为零 [英] setting edittext value to zero when empty and removing zero when any entry is made

问题描述

我有两个用于显示数学函数结果的edittext字段.我有两个问题.我想在两种情况下将文本编辑为零值:第一个:我希望编辑文本为空时自动将其变为零

I have two edittext fields that i am using to display results of mathematical functions. I have two problems. I want to edit text to have a value of zero in two scenarios: 1st: I want the edit text value to automatically become zero if the edit text is empty

第二:如果用户删除字段值直到编辑文本为空.

2nd: if a user erases field values till the edit text is empty.

更新:我可以用setText()或android:text ="0"进行排序的第一个问题，但是当尝试解决第二个问题时，它就很棘手

UPDATE: The 1st problem I can sort with a setText() or android:text="0" but when trying to also solve the 2nd it becomes tricky

推荐答案

尝试如下操作:

final EditText et = new EditText(this);
et.addTextChangedListener(new TextWatcher() {
    @Override
    public void beforeTextChanged(CharSequence s, int start, int count, int after) {

    }

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

    }

    @Override
    public void afterTextChanged(Editable s) {
        if(et.getText().length() == 0){
            et.setText("0");
        }
    }
});

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