Exploring the ImageView of Android controls

The ImageView control is an image control that displays images.

The following simulated mobile phone Image Viewer

Directory structure

Main. xml layout File

<? Xml version = "1.0" encoding = "UTF-8"?>
<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Android: orientation = "vertical"
Android: layout_width = "fill_parent"
Android: layout_height = "fill_parent">
<ImageView android: id = "@ + id/imageView"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: layout_gravity = "center_horizontal"
Android: src = "@ drawable/p1"/>
<LinearLayout xmlns: android = "http://schemas.android.com/apk/res/android"
Android: orientation = "horizontal"
Android: layout_width = "fill_parent"
Android: layout_height = "wrap_content"
Android: layout_gravity = "center_horizontal">
<Button android: id = "@ + id/previous"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "previous"
Android: layout_gravity = "center_horizontal"/>
<Button android: id = "@ + id/alpha_plus"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "Increased transparency"
Android: layout_gravity = "center_horizontal"/>
<Button android: id = "@ + id/alpha_minus"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "reduced transparency"
Android: layout_gravity = "center_horizontal"/>
<Button android: id = "@ + id/next"
Android: layout_width = "wrap_content"
Android: layout_height = "wrap_content"
Android: text = "Next"
Android: layout_gravity = "center_horizontal"/>
</LinearLayout>
</LinearLayout>

ImageViewActivity class

Package com. ljq. iv;

Import android. app. Activity;
Import android. OS. Bundle;
Import android. view. View;
Import android. widget. Button;
Import android. widget. ImageView;

Public class ImageViewActivity extends Activity {
Private ImageView imageView = null;
Private Button previous = null; // previous
Private Button next = null; // The next
Private Button alpha_plus = null; // increased transparency
Private Button alpha_minus = null; // reduced transparency
Private int currentImgId = 0; // record the image id displayed in the current ImageView
Private int alpha = 255; // record ImageView transparency
Int [] imgId = {// Image array displayed in ImageView
R. drawable. p1,
R. drawable. p2,
R. drawable. p3,
R. drawable. p4,
R. drawable. p5,
R. drawable. p6,
R. drawable. p7,
R. drawable. p8,
};

@ Override
Public void onCreate (Bundle savedInstanceState ){
Super. onCreate (savedInstanceState );
SetContentView (R. layout. main );

ImageView = (ImageView) findViewById (R. id. imageView );
Previous = (Button) findViewById (R. id. previous );
Next = (Button) findViewById (R. id. next );
Alpha_plus = (Button) findViewById (R. id. alpha_plus );
Alpha_minus = (Button) findViewById (R. id. alpha_minus );

Previous. setOnClickListener (listener );
Next. setOnClickListener (listener );
Alpha_plus.setOnClickListener (listener );
Alpha_minus.setOnClickListener (listener );
}

Private View. OnClickListener listener = new View. OnClickListener (){

Public void onClick (View v ){
If (v = previous ){
CurrentImgId = (currentImgId-1 + imgId. length) % imgId. length;
ImageView. setImageResource (imgId [currentImgId]);
}
If (v = next ){
CurrentImgId = (currentImgId + 1) % imgId. length;
ImageView. setImageResource (imgId [currentImgId]);
}
If (v = alpha_plus ){
Alpha + = 10;
If (alpha & gt; 255 ){
Alpha = 255;
}
ImageView. setAlpha (alpha );
}
If (v = alpha_minus ){
Alpha-= 10;
If (alpha <0 ){
Alpha = 0;
}
ImageView. setAlpha (alpha );
}
}

};

}

Running result