Android中使用SeekBar拖动条实现改变图片透明度(代码实现)

<&＃63;xml version="1.0" encoding="utf-8"&＃63;>

  
  

package com.badao.relativelayouttest;
import androidx.annotation.RequiresApi;
import androidx.appcompat.app.AppCompatActivity;
import android.os.Build;
import android.os.Bundle;
import android.widget.ImageView;
import android.widget.SeekBar;
public class SeekBarActivity extends AppCompatActivity {
  private SeekBar seekBar;
  private ImageView imageView;
  @Override
  protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_seek_bar);
    imageView = (ImageView) findViewById(R.id.image);
    seekBar = (SeekBar) findViewById(R.id.seekBar);
    seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() {
      @RequiresApi(api = Build.VERSION_CODES.JELLY_BEAN)
      @Override
      public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {
        imageView.setImageAlpha(progress);
      }
      @Override
      public void onStartTrackingTouch(SeekBar seekBar) {
      }
      @Override
      public void onStopTrackingTouch(SeekBar seekBar) {
      }
    });
  }
}