我有一个情况，有两个领域。Field1和field2。我想要的
当field1被改变时，要做的是空field2，反之亦然。所以只有在最后
一个字段上有内容。
field1 = (EditText)findViewById(R.id.field1);
field2 = (EditText)findViewById(R.id.field2);
field1.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
}
public void onTextChanged(CharSequence s, int start,
int before, int count) {
field2.setText("");
}
});
field2.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
}
public void onTextChanged(CharSequence s, int start,
int before, int count) {
field1.setText("");
}
});
它工作得很好，如果我附加addTextChangedListener到field1，但当
我对两个字段都这么做，应用程序崩溃了。显然是因为他们想要改变
无限地相互联系。一旦field1改变，此时它就会清除field2
Field2被更改，因此它将清除field1，以此类推……
谁能给点建议吗?
您可以添加一个检查，只在字段中的文本不为空时清除(即当长度不等于0时)。
field1.addTextChangedListener(new TextWatcher() {
@Override
public void afterTextChanged(Editable s) {}
@Override
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start,
int before, int count) {
if(s.length() != 0)
field2.setText("");
}
});
field2.addTextChangedListener(new TextWatcher() {
@Override
public void afterTextChanged(Editable s) {}
@Override
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
}
@Override
public void onTextChanged(CharSequence s, int start,
int before, int count) {
if(s.length() != 0)
field1.setText("");
}
});
这里是TextWatcher的文档。
另外，请尊重命名约定。
我知道这很旧了，但某天有人可能会再次看到它。
I had a similar problem where I would call setText on a EditText and onTextChanged would be called when I didn't want it to. My first solution was to write some code after calling setText() to undo the damage done by the listener. But that wasn't very elegant.
After doing some research and testing I discovered that using getText().clear() clears the text in much the same way as setText(""), but since it isn't setting the text the listener isn't called, so that solved my problem. I switched all my setText("") calls to getText().clear() and I didn't need the bandages anymore, so maybe that will solve your problem too.
试试这个:
Field1 = (EditText)findViewById(R.id.field1);
Field2 = (EditText)findViewById(R.id.field2);
Field1.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
}
public void onTextChanged(CharSequence s, int start,
int before, int count) {
Field2.getText().clear();
}
});
Field2.addTextChangedListener(new TextWatcher() {
public void afterTextChanged(Editable s) {}
public void beforeTextChanged(CharSequence s, int start,
int count, int after) {
}
public void onTextChanged(CharSequence s, int start,
int before, int count) {
Field1.getText().clear();
}
});
这个回答有点晚了，但这里有一个可重复使用的解决方案:
/**
* An extension of TextWatcher which stops further callbacks being called as
* a result of a change happening within the callbacks themselves.
*/
public abstract class EditableTextWatcher implements TextWatcher {
private boolean editing;
@Override
public final void beforeTextChanged(CharSequence s, int start,
int count, int after) {
if (editing)
return;
editing = true;
try {
beforeTextChange(s, start, count, after);
} finally {
editing = false;
}
}
protected abstract void beforeTextChange(CharSequence s, int start,
int count, int after);
@Override
public final void onTextChanged(CharSequence s, int start,
int before, int count) {
if (editing)
return;
editing = true;
try {
onTextChange(s, start, before, count);
} finally {
editing = false;
}
}
protected abstract void onTextChange(CharSequence s, int start,
int before, int count);
@Override
public final void afterTextChanged(Editable s) {
if (editing)
return;
editing = true;
try {
afterTextChange(s);
} finally {
editing = false;
}
}
public boolean isEditing() {
return editing;
}
protected abstract void afterTextChange(Editable s);
}
因此，当使用上述方法时，在TextWatcher中发生的任何setText()调用都不会导致TextWatcher再次被调用:
/**
* A setText() call in any of the callbacks below will not result in TextWatcher being
* called again.
*/
public class MyTextWatcher extends EditableTextWatcher {
@Override
protected void beforeTextChange(CharSequence s, int start, int count, int after) {
}
@Override
protected void onTextChange(CharSequence s, int start, int before, int count) {
}
@Override
protected void afterTextChange(Editable s) {
}
}
如果你正在使用Kotlin进行Android开发，那么你可以使用以下代码添加TextChangedListener():
myTextField.addTextChangedListener(object : TextWatcher{
override fun afterTextChanged(s: Editable?) {}
override fun beforeTextChanged(s: CharSequence?, start: Int, count: Int, after: Int) {}
override fun onTextChanged(s: CharSequence?, start: Int, before: Int, count: Int) {}
})
我写了自己的扩展，对我很有帮助。(芬兰湾的科特林)
你可以这样写:
editText.customAfterTextChanged { editable ->
//You have accessed the editable object.
}
我的分机号:
fun EditText.customAfterTextChanged(action: (Editable?)-> Unit){
this.addTextChangedListener(object : TextWatcher {
override fun beforeTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {}
override fun onTextChanged(p0: CharSequence?, p1: Int, p2: Int, p3: Int) {}
override fun afterTextChanged(editable: Editable?) {
action(editable)
}
})}
editText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (noteid != -1) {
MainActivity.notes.set(noteid, String.valueOf(charSequence));
MainActivity.arrayAdapter.notifyDataSetChanged();
}
}
@Override
public void afterTextChanged(Editable editable) {
}
});
在这段代码中，noteid基本上是被收回的参数，它被放入缩进中或通过缩进传递。
Intent intent = getIntent();
noteid = intent.getIntExtra("noteid", -1);
下面的代码基本上是额外的代码，如果你想更清楚地理解的话。
how to make the menu or insert the menu in our code ,
create the menu folder this the folder created by going into the raw
->rightclick->
directory->name the folder as you wish->
then click on the directory formed->
then click on new file and then name for file as you wish ie the folder name file
and now type the 2 lines code in it and see the magic.
新的活动代码命名为NoteEditor.java用于编辑目的，我的应用程序基本上是笔记应用程序。
package com.example.elavi.notes;
import android.content.Intent;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.widget.EditText;
import android.widget.Toast;
import static android.media.CamcorderProfile.get;
public class NoteEditorActivity extends AppCompatActivity {
EditText editText;
int noteid;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_note_editor);
editText = findViewById(R.id.editText);
Intent intent = getIntent();
noteid = intent.getIntExtra("noteid", -1);
if (noteid != -1) {
String text = MainActivity.notes.get(noteid);
editText.setText(text);
Toast.makeText(getApplicationContext(),"The arraylist content is"+MainActivity.notes.get(noteid),Toast.LENGTH_SHORT).show();
}
else
{
Toast.makeText(getApplicationContext(),"Here we go",Toast.LENGTH_SHORT).show();
MainActivity.notes.add("");
noteid=MainActivity.notes.size()-1;
}
editText.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (noteid != -1) {
MainActivity.notes.set(noteid, String.valueOf(charSequence));
MainActivity.arrayAdapter.notifyDataSetChanged();
}
}
@Override
public void afterTextChanged(Editable editable) {
}
});
}
}
我们可以在编辑文本之前删除字段的TextWatcher，然后在编辑文本之后将其添加回来。
将field1和field2的文本监视器声明为单独的变量，并为它们命名:例如field1
private TextWatcher Field_1_Watcher = new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
}
@Override
public void afterTextChanged(Editable s) {
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
}
};
然后使用它的名称添加该监视程序:
field1. addtextchangedlistener (Field_1_Watcher)用于field1，和
field2. addtextchangedlistener (Field_2_Watcher)用于field2
在修改field2文本之前，删除TextWatcher:
field2.removeTextChangedListener (Field_2_Watcher)
修改文本:
field2.setText (" ")
然后将TextWatcher添加回来:
field2.addTextChangedListener (Field_2_Watcher)
对另一个字段做同样的处理
另一个可能会帮助别人的解决方案。有2个EditText，它们在编辑后相互改变。默认情况下，它导致了周期性。
使用变量:
Boolean uahEdited = false;
Boolean usdEdited = false;
添加TextWatcher
uahEdit = findViewById(R.id.uahEdit);
usdEdit = findViewById(R.id.usdEdit);
uahEdit.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
if (!usdEdited) {
uahEdited = true;
}
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
String tmp = uahEdit.getText().toString();
if(!tmp.isEmpty() && uahEdited) {
uah = Double.valueOf(tmp);
usd = uah / 27;
usdEdit.setText(String.valueOf(usd));
} else if (tmp.isEmpty()) {
usdEdit.getText().clear();
}
}
@Override
public void afterTextChanged(Editable s) {
uahEdited = false;
}
});
usdEdit.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence s, int start, int count, int after) {
if (!uahEdited) {
usdEdited = true;
}
}
@Override
public void onTextChanged(CharSequence s, int start, int before, int count) {
String tmp = usdEdit.getText().toString();
if (!tmp.isEmpty() && usdEdited) {
usd = Double.valueOf(tmp);
uah = usd * 27;
uahEdit.setText(String.valueOf(uah));
} else if (tmp.isEmpty()) {
uahEdit.getText().clear();
}
}
@Override
public void afterTextChanged(Editable s) {
usdEdited = false;
}
});
不要批评太多。我是一个开发新手
你用这个
我已经提供了textchangelistner的最新方法
edMsg.addTextChangedListener(new TextWatcher() {
@Override
public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) {
}
@Override
public void onTextChanged(CharSequence charSequence, int i, int i1, int i2) {
if (i2 == 0){
////Edit text blanked
}
String msg = charSequence.toString();/// your text on changed in edit text
}
@Override
public void afterTextChanged(Editable editable) {
}
});
