An example of a picture viewer that can be adjusted transparently by Android _android

This article illustrates an example of an Android based image viewer implementation that can be used to adjust transparency, as follows:

main.xml Part of the code is as follows:

<?xml version= "1.0" encoding= "Utf-8"?> <linearlayout xmlns:android= "http://schemas.android.com/apk/res/" Android "Android:layout_width=" Fill_parent "android:layout_height=" fill_parent "android:orientation=" vertical " > <linearlayout android:layout_width= "match_parent" android:layout_height= "wrap_content" > <Bu
      Tton android:id= "@+id/button1" android:layout_width= "wrap_content" android:layout_height= "Wrap_content" 
      android:text= "Increase transparency"/> <button android:id= "@+id/button2" android:layout_width= "Wrap_content" android:layout_height= "wrap_content" android:text= "reduce transparency"/> <button android:id= "@+id/button" 3 "android:layout_width=" Wrap_content "android:layout_height=" Wrap_content "android:text=" Next "/> & Lt;/linearlayout> <!--define ImageView--> <imageview android:id= "@+id/imageview1" to display the overall picture Android:lay Out_width= "Wrap_content" android:layout_height= "Wrap_content" android:background= "#0000ff" android:scaletype= "Fitcenter" android:src= "@drawable Shuangta "/> <!--defines imageview--> <imageview android:id=" @+id/imageview2 "that display local images Android:layout_w Idth= "Wrap_content" android:layout_height= "wrap_content" android:layout_margintop= "10DP" android:background= "#

 0000ff "/> </LinearLayout>

The

Java part of the code is:

Package Android.demo;
Import android.app.Activity;
Import Android.graphics.Bitmap;
Import Android.graphics.BitmapFactory;
Import android.graphics.drawable.BitmapDrawable;
Import Android.os.Bundle;
Import android.view.MotionEvent;
Import Android.view.View;
Import Android.view.View.OnClickListener;
Import Android.view.View.OnTouchListener;
Import Android.widget.Button;

Import Android.widget.ImageView; public class Androiddemo5activity extends activity {//define an array to access the picture int[] images = new int[] {R.drawable.lijiang, R.D
  Rawable.qiao, R.drawable.shuangta, R.drawable.shui, R.drawable.xiangbi, R.drawable.ic_launcher,};
  Defines the currently displayed picture int currentimage = 2;

  Defines the initial transparency of a picture private int alpha = 255; @Override protected void OnCreate (Bundle savedinstancestate) {//TODO auto-generated method stub super.oncreate
    (savedinstancestate);
    Setcontentview (R.layout.main);
    Final Button Plusbutton = (Button) Findviewbyid (R.id.button1); Final Button Minuxbutton = (Button) Findviewbyid (R.id.button2);

    Final Button Nextbutton = (Button) Findviewbyid (R.id.button3);
    Final ImageView Imageview1 = (imageview) Findviewbyid (R.ID.IMAGEVIEW1);

    Final ImageView imageview2 = (imageview) Findviewbyid (R.ID.IMAGEVIEW2); Defines the time listener Nextbutton.setonclicklistener to view the next picture (new Onclicklistener () {@Override public void OnClick (Vi
        EW v) {if (Currentimage >= 5) {currentimage =-1;
        } bitmapdrawable bitmap = (bitmapdrawable) imageview1. getdrawable ();
        If the picture has not been reclaimed, force the recall of the picture if (!bitmap.getbitmap (). isrecycled ()) {Bitmap.getbitmap (). Recycle (); ///change ImageView picture Imageview1.setimagebitmap (Bitmapfactory.decoderesource (getresources), IM
      Ages[++currentimage]));

    }
    }); Define a way to change the transparency of a picture onclicklistener listener = new Onclicklistener () {@Override public void OnClick (View v) {if (v = = Plusbutton) {alpha + 20;
        } if (v = = Minuxbutton) {alpha-= 20;
        } if (Alpha > 255) {alpha = 255;
        } if (Alpha <= 0) {alpha = 0;

      //Change the transparency of the picture Imageview1.setalpha (Alpha);

    }
    };
    Add Listener Plusbutton.setonclicklistener (Listener) for 2 buttons;
    Minuxbutton.setonclicklistener (listener);  Imageview1.setontouchlistener (New Ontouchlistener () {@Override public boolean Ontouch (View arg0, motionevent
            ARG1) {//TODO auto-generated method stub bitmapdrawable Bitmapdeaw = (bitmapdrawable) imageview1
        . getdrawable ();
        Gets the bitmap in the first picture display box Bitmap Bitmap = Bitmapdeaw.getbitmap ();
        Double scale = bitmap.getwidth ();
        You may need to display the start point int x = (int) (ARG1.GETX () * scale) of the picture;
        int y = (int) (arg1.gety () * scale);
        if (x + > Bitmap.getwidth ()) {x = Bitmap.getwidth ()-120; }
        if (Y + > Bitmap.getheight ()) {y = Bitmap.getheight ()-120;
        ///Display the specified area of the picture Imageview2.setimagebitmap (Bitmap.createbitmap (Bitmap, x, y, 120, 120));
        Imageview2.setalpha (Alpha);
      return false;
  }
    });

 }

}

The Operation effect chart is as follows: