Android控件-SeekBar

一. 简介

android.view.View
  ↳android.widget.ProgressBar
     ↳android.widget.AbsSeekBar 
        ↳android.widget.SeekBar

SeekBar继承于ProgressBar，那么ProgressBar有的属性，我们SeekBar也有。SeekBar多了一个thumb属性，用来设置滑块的图标。

二. 属性

android:max=""              //最大进度值
  
android:progress=""         //当前进度值

android:secondaryProgress=""//第二进度的值，常用来作为进度值的背景或者缓存进度
  
android:progressDrawable="" //progress的样式
  
android:thumb=""            //滑块的图标

三. 自定义progressDrawable

1 2	//使用方式 android:progressDrawable="@drawable/progressbar_bg"

<!--drawable文件夹下面的progressbar_bg-->
<?xml version="1.0" encoding="utf-8"?>
<layer-list xmlns:android="http://schemas.android.com/apk/res/android">

    <!--设置背景颜色-->
    <item android:id="@android:id/background"
        android:drawable="@color/colorProgress"
        />

    <!--设置缓冲条进度-->
    <item android:id="@android:id/secondaryProgress">
        <clip>
            <shape>
                <!--圆角-->
                <corners android:radius="50dp"/>
               
                <!--进度条渐变颜色的初值和结束值-->
                <gradient
                    android:endColor="#D2D2B0"
                    android:startColor="#D2D2B0"
                    />
            </shape>
        </clip>
    </item>

    <!--设置进度条颜色-->
    <item android:id="@android:id/progress">
        <clip>
            <shape>
                <!--圆角-->
                <corners android:radius="50dp"/>
                
                <!--进度条渐变颜色的初值和结束值-->
                <gradient
                    android:endColor="#fff000"
                    android:startColor="#fff000"
                    />
            </shape>
        </clip>
    </item>

</layer-list>

四. 监听滑动

SeekBar seekBar = findViewById(R.id.seek_bar);

seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
    @Override
    public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        //进度发生改变时会触发
    }

    @Override
    public void onStartTrackingTouch(SeekBar seekBar) {
        //按住SeekBar时会触发
    }

    @Override
    public void onStopTrackingTouch(SeekBar seekBar) {
        //放开SeekBar时触发
    }
});

五. demo

//active_main.xml
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout 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=".MainActivity"
    android:orientation="vertical"
    android:gravity="center">

    <SeekBar
        style="@style/Widget.AppCompat.SeekBar"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:layout_marginTop="40dp"
        android:indeterminate="false"
        android:max="100"
        android:progress="80"
        android:secondaryProgress="100" />

    <SeekBar
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:progressDrawable="@drawable/seekbar_bg"
        android:max="100"
        android:progress="80"
        android:secondaryProgress="100"
        android:thumb="@drawable/seek_bar_point"
        android:layout_marginTop="40dp"
        />

    <SeekBar
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:progressDrawable="@drawable/seekbar_bg"
        android:max="100"
        android:progress="80"
        android:secondaryProgress="100"
        android:thumb="@drawable/seek_bar_point"
        android:background="@null"
        android:layout_marginTop="40dp"
        />

    <SeekBar
        android:id="@+id/seek_bar"
        android:layout_width="match_parent"
        android:layout_height="40dp"
        android:progressDrawable="@drawable/seekbar_bg"
        android:max="100"
        android:progress="80"
        android:secondaryProgress="100"
        android:thumb="@drawable/seek_bar_point"
        android:splitTrack="false"
        android:background="@null"
        android:layout_marginTop="40dp"
        />

    <TextView
        android:id="@+id/show_text"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:textSize="20sp"
        android:text="80"
        android:textAlignment="center"
        android:textStyle="bold"
        android:layout_marginTop="40dp"
        />

</LinearLayout>
          
//MainActivity
public class MainActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        final TextView textView = findViewById(R.id.show_text);

        SeekBar seekBar = findViewById(R.id.seek_bar);

        seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
            @Override
            public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
                textView.setText(String.valueOf(progress));
            }

            @Override
            public void onStartTrackingTouch(SeekBar seekBar) {

            }

            @Override
            public void onStopTrackingTouch(SeekBar seekBar) {

            }
        });
    }
}