EditText监听方法，实时的判断输入多少字符

2019-12-12 04:15:27

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最近在写一个小项目，其中有一点用到了显示EditText中输入了多少个字符，像微博中显示剩余多少字符的功能。在EditText提供了一个方法addTextChangedListener实现对输入文本的监控。下边是我自己写的一个Demo。

代码实现：

布局文件main.xml

[html] view plain copy<?xml version="1.0" encoding="utf-8"?> <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"  android:orientation="vertical"  android:layout_width="fill_parent"  android:layout_height="fill_parent"  > <TextView android:id="@+id/tv"  android:layout_width="fill_parent"  android:layout_height="wrap_content"  android:textColor="@android:color/white"  android:text="Please input the text:"  /> <EditText android:id="@+id/ET"  android:layout_width="match_parent"  android:layout_height="wrap_content"  /> </LinearLayout>

Activity

[java] view plain copypackage com.damai.test; import android.app.Activity; import android.os.Bundle; import android.text.Editable; import android.text.TextWatcher; import android.widget.EditText; import android.widget.TextView; import android.widget.Toast; public class TestActivity extends Activity {  private TextView mTextView;  private EditText mEditText;  @Override  public void onCreate(Bundle savedInstanceState) {   super.onCreate(savedInstanceState);   setContentView(R.layout.main);   mTextView = (TextView)findViewById(R.id.tv);   mEditText = (EditText)findViewById(R.id.ET);   mEditText.addTextChangedListener(mTextWatcher);  }  TextWatcher mTextWatcher = new TextWatcher() {   private CharSequence temp;   private int editStart ;   private int editEnd ;   @Override   public void onTextChanged(CharSequence s, int start, int before, int count) {    // TODO Auto-generated method stub     temp = s;   }   @Override   public void beforeTextChanged(CharSequence s, int start, int count,     int after) {    // TODO Auto-generated method stub //   mTextView.setText(s);//将输入的内容实时显示   }   @Override   public void afterTextChanged(Editable s) {    // TODO Auto-generated method stub    editStart = mEditText.getSelectionStart();    editEnd = mEditText.getSelectionEnd();    mTextView.setText("您输入了" + temp.length() + "个字符");    if (temp.length() > 10) {     Toast.makeText(TestActivity.this,       "你输入的字数已经超过了限制！", Toast.LENGTH_SHORT)       .show();     s.delete(editStart-1, editEnd);     int tempSelection = editStart;     mEditText.setText(s);     mEditText.setSelection(tempSelection);    }   }  }; }