Android拖动条的实现代码

<?xml version="1.0" encoding="utf-8"?> 
<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android" 
 xmlns:app="http://schemas.android.com/apk/res-auto" 
 xmlns:tools="http://schemas.android.com/tools" 
 android:layout_width="match_parent" 
 android:layout_height="match_parent" 
 tools:context="com.amy.seekbartest.MainActivity"> 
 
 <TextView 
  android:id="@+id/textView1" 
  android:layout_width="wrap_content" 
  android:layout_height="wrap_content" 
  android:text="当前值：50" 
  android:textSize="16sp" 
  android:paddingTop="40dp" 
  android:paddingLeft="15dp" 
  tools:layout_editor_absoluteY="0dp" 
  tools:layout_editor_absoluteX="0dp" /> 
 <!-- 拖动条 --> 
 <SeekBar 
  android:id="@+id/seekBar1" 
  android:layout_height="wrap_content" 
  android:max="100" 
  android:layout_width="match_parent" 
  android:progress="50" 
  android:paddingTop="10dp" 
  tools:layout_editor_absoluteY="0dp" 
  tools:layout_editor_absoluteX="32dp" /> 
</android.support.constraint.ConstraintLayout> 

package com.amy.seekbartest; 
 
import android.support.v7.app.AppCompatActivity; 
import android.os.Bundle; 
import android.view.View; 
import android.widget.SeekBar; 
import android.widget.TextView; 
import android.widget.Toast; 
 
public class MainActivity extends AppCompatActivity { 
 
 private SeekBar seekBar;//拖动条 
 @Override 
 protected void onCreate(Bundle savedInstanceState) { 
  super.onCreate(savedInstanceState); 
  setContentView(R.layout.activity_main); 
  final TextView result = (TextView) findViewById(R.id.textView1); 
  seekBar = (SeekBar) findViewById(R.id.seekBar1); 
  seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { 
   @Override 
   public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) { 
    result.setText("当前值："+progress); 
   } 
 
   @Override 
   public void onStartTrackingTouch(SeekBar seekBar) { 
    Toast.makeText(MainActivity.this,"开始滑动",Toast.LENGTH_SHORT).show(); 
   } 
 
   @Override 
   public void onStopTrackingTouch(SeekBar seekBar) { 
    Toast.makeText(MainActivity.this,"结束滑动",Toast.LENGTH_SHORT).show(); 
   } 
  }); 
 } 
}