<RelativeLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent" android:layout_height="match_parent" android:paddingBottom="@dimen/activity_vertical_margin" android:paddingLeft="@dimen/activity_horizontal_margin" android:paddingRight="@dimen/activity_horizontal_margin" android:paddingTop="@dimen/activity_vertical_margin" tools:context=".MainActivity" > <ImageView android:id="@+id/imageView1" android:layout_width="wrap_content" android:layout_height="wrap_content" android:layout_alignRight="@+id/progressBar1" android:layout_alignTop="@+id/textView1" android:src="@drawable/bg" /> <SeekBar android:id="@+id/seekBar1" android:layout_width="match_parent" android:layout_height="wrap_content" android:layout_alignBottom="@+id/imageView1" android:layout_alignLeft="@+id/imageView1" android:max="100" android:layout_marginBottom="22dp" /> </RelativeLayout>
package com.example.progresstest;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.ProgressBar;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;
import android.widget.TextView;
public class MainActivity extends Activity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//图片的透明度setalpha()
final ImageView img = (ImageView) findViewById(R.id.imageView1);
SeekBar seekBar = (SeekBar) findViewById(R.id.seekBar1);
seekBar.setOnSeekBarChangeListener(new OnSeekBarChangeListener() {
@Override
public void onStopTrackingTouch(SeekBar seekBar) {
img.setAlpha(seekBar.getProgress());
}
@Override
public void onStartTrackingTouch(SeekBar seekBar) {
// TODO Auto-generated method stub
}
@Override
public void onProgressChanged(SeekBar seekBar, int progress,
boolean fromUser) {
// TODO Auto-generated method stub
}
});
}
重点：1.要使用setalpha(int alpha) 其中alpha为1~255之间的数值。
2.通过SeekBar.getprogess()获取到当前progress的数值；
3.监听器是onSeekBarChangeListener();
版权所有，盗版必需说明。
原文：http://www.cnblogs.com/duoluo-lin/p/5277136.html