<?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="當前值：50"   android:textSize="16sp"   android:paddingTop="40dp"   android:paddingLeft="15dp"   tools:layout_editor_absoluteY="0dp"   tools:layout_editor_absoluteX="0dp" />  <!-- 拖動條 -->  <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;//拖動條  @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("當前值："+progress);    }     @Override    public void onStartTrackingTouch(SeekBar seekBar) {     Toast.makeText(MainActivity.this,"開始滑動",Toast.LENGTH_SHORT).show();    }     @Override    public void onStopTrackingTouch(SeekBar seekBar) {     Toast.makeText(MainActivity.this,"結束滑動",Toast.LENGTH_SHORT).show();    }   });  } }