android：实时监听键盘表单输入的值。

╰半夏微凉° 2022-01-11 17:59 506阅读 0赞

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ExNDI0MjYxMzAz_size_16_color_FFFFFF_t_70]

##### layout/activity\_jinapanjianting.xml #####

<?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="match_parent" android:layout_height="wrap_content" android:textColor="@android:color/black" android:text="Please input the text:" />
        <EditText android:id="@+id/ET" android:layout_width="match_parent" android:layout_height="wrap_content" />
    </LinearLayout>

##### jinapanjianting.java #####

package com.example.asus.jichuzujian;
    
    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.TextView;
    import android.widget.Toast;
    
    public class jinapanjianting extends AppCompatActivity { 
        private TextView mTextView;
        private EditText mEditText;
    
        @Override
        protected void onCreate(Bundle savedInstanceState) { 
            super.onCreate(savedInstanceState);
            setContentView(R.layout.activity_jinapanjianting);
            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;
                Toast.makeText(getApplicationContext(),"1",Toast.LENGTH_LONG).show();
    
            }
            @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.toString()+ "个字符");
                Toast.makeText(getApplicationContext(),"1",Toast.LENGTH_LONG).show();
    // if (temp.length() > 10) { 
    // Toast.makeText(jinapanjianting.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);
    // }
            }
        };
    }

上边temp.toString()是用来获取内容的，  
temp.length（）可以实时获取输入内容的长度。

[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2ExNDI0MjYxMzAz_size_16_color_FFFFFF_t_70]: /images/20220110/07ba211cbb934b548eb3eb0a36e00c5f.png