SeekBar拖动条的功能和用法
拖动条和进度条比较相似，拖动条通过滑块的位置标识数值
。拖动条允许用户拖动滑块改变数值
public class MainActivity extends Activity {
ImageView iv;
SeekBar seb;
@Override
protected void onCreate(Bundle savedInstanceState) {
// TODO Auto-generated method stub
super.onCreate(savedInstanceState);
setContentView(R.layout.seekbar);
iv=(ImageView) findViewById(R.id.photo);
seb=(SeekBar) findViewById(R.id.seekbar);
seb.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
@Override
public void onStartTrackingTouch(SeekBar arg0) {
// TODO Auto-generated method stub
}
//当滑块位置发生改变是触发该方法
@Override
public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
// TODO Auto-generated method stub
//设置图片透明度
iv.setImageAlpha(arg1);
}
});
}
}
<?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" >
<ImageView
android:id="@+id/photo"
android:layout_width="match_parent"
android:layout_height="240dp"
android:src="@drawable/mia10"/>
<!-- 定义 一个拖动条，并改变滑块外观
android:progress="255"/>进度条已完成进度值
android:max="255"进度条最大值-->
<SeekBar
android:id="@+id/seekbar"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:max="255"
android:progress="255"
android:thumb="@drawable/mia4"/>
</LinearLayout>
