SeekBar

SeekBar的使用很简单，和其他控件一样，先在布局文件中声明，然后在Activity中使用。

下面演示下使用SeekBar改变图片的透明度：

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1.java文件

package gdp.seekbartest;

import android.annotation.SuppressLint;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.widget.ImageView;
import android.widget.SeekBar;
import android.widget.SeekBar.OnSeekBarChangeListener;

public class MianActivity extends Activity {
    private ImageView imageView ;
    private SeekBar seekBar ;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.mian);
        
        imageView = (ImageView)findViewById(R.id.imageView);
        seekBar = (SeekBar)findViewById(R.id.seekBar);
        seekBar.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
                
            }
            
            @SuppressLint("NewApi")
            @Override
            public void onProgressChanged(SeekBar arg0, int arg1, boolean arg2) {
                // TODO Auto-generated method stub
                imageView.setImageAlpha(arg1);
            }
        });
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu) {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.mian, menu);
        return true;
    }

}

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2.xml文件

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
    android:orientation="vertical" >

    <ImageView
        android:id="@+id/imageView"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:src="@drawable/home" />

    <!-- 定义seekbar，并改变滑块外观 -->

    <SeekBar
        android:id="@+id/seekBar"
        android:layout_width="fill_parent"
        android:layout_height="wrap_content"
        android:max="255"
        android:progress="255"
        />
</LinearLayout>