Android开发之SeekBar基本使用及各种美观样式示例

public class MainActivity extends Activity {
  ImageView imageView;
  Toolbar toolbar;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    imageView = (ImageView) findViewById(R.id.image);
    toolbar = (Toolbar) findViewById(R.id.toolbar);
    SeekBar seekBar = (SeekBar) findViewById(R.id.seekbar);
    SeekBar seekBar02 = (SeekBar) findViewById(R.id.seekbar02);
    seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
      @Override
      public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        imageView.setAlpha(progress);
      }
      @Override
      public void onStartTrackingTouch(SeekBar seekBar) { }
      @Override
      public void onStopTrackingTouch(SeekBar seekBar) { }
    });
    seekBar02.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
      @Override
      public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        toolbar.getBackground().setAlpha(progress);
      }
      @Override
      public void onStartTrackingTouch(SeekBar seekBar) { }
      @Override
      public void onStopTrackingTouch(SeekBar seekBar) { }
    });
  }
}

<?xml version="1.0" encoding="utf-8" ?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
  android:layout_width="match_parent"
  android:layout_height="match_parent"
  android:orientation="vertical">
  <android.support.v7.widget.Toolbar
    android:id="@+id/toolbar"
    android:layout_width="match_parent"
    android:layout_height="50dp"
    android:background="#ff000000">
    <TextView
      android:layout_width="match_parent"
      android:layout_height="wrap_content"
      android:text="这里是toolBar~"/>
  </android.support.v7.widget.Toolbar>
  <ImageView
    android:id="@+id/image"
    android:layout_width="match_parent"
    android:layout_height="300dp"
    android:src="@drawable/huangjindiao"
    android:padding="20dp"/>
  <!--定义一个拖动条滑动来改变它的外观-->
  <SeekBar
    android:id="@+id/seekbar"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    android:max="255"
    android:progress="255"
    android:thumb="@drawable/ok"/>
</LinearLayout>