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?


当前回答

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) {

            }
        });
    }
}

其他回答

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

你也可以使用hasFocus()方法:

public void onTextChanged(CharSequence s, int start,
     int before, int count) {
     if (Field2.hasfocus()){
         Field1.setText("");
     }
   }

我在大学作业中测试了这个方法,在用户输入温标时转换温标。效果很好,而且简单多了。

editText.addTextChangedListener(new TextWatcher() 
{
            @Override
            public void beforeTextChanged(CharSequence charSequence, int i, int i1, int i2) 
            {
            }

            @Override
            public void onTextChanged(CharSequence chr, int i, int i1, int i2) 
            {
                //Check char sequence is empty or not
                if (chr.length() > 0)
                {
                    //Your Code Here
                }
            }

            @Override
            public void afterTextChanged(Editable editable) 
            {
            }
 });

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