Image sliding gradient

Source code introduction: Android image sliding gradient to achieve animation effects.

Source code effect:

Source code snippet:

 package com.example.tz_demo_8_14; 
  
 import android.graphics.Canvas;
 import android.graphics.ColorFilter;
 import android.graphics.Rect;
 import android.graphics.drawable.Drawable;
 import android.util.Log;
 import android.view.Gravity; 
  
 public   class RevealDrawable extends Drawable { 
  
 private Drawable mUnSelectedDrawable;
 private Drawable mSelectedDrawable;
 private Rect outRect = new Rect(); 
  
 public RevealDrawable(Drawable unSelectedDrawable, Drawable selectedDrawable) {
 this .mUnSelectedDrawable = unSelectedDrawable;
 this .mSelectedDrawable = selectedDrawable;
 } 
  
 /**
 * level:0~10000 Full color: 5000 Full gray: 0||10000 Gradient color: 5000~10000
 */  
 @Override  
 public   void draw(Canvas canvas) { 
          
 int level = getLevel();
 if (level == 0 || level == 10000 ) {
 // All gray  
            mUnSelectedDrawable.draw(canvas);
 } else   if (level == 5000 ) {
 // Full color  
            mSelectedDrawable.draw(canvas);
 } else {
 // Gradient color (part gray, part color):  
 // Get the rectangular boundaries of the current Drawable  
            Rect bounds = getBounds();
 Rect r = outRect; 
              
 { // 1. Cut out the left part of the rectangle from the gray image  
 //level:0~5000~10000  
 float ratio = (level / 5000f) - 1f;
 int w = bounds.width();
                w = ( int ) (w * Math.abs(ratio));
 int h = bounds.height();
 int gravity = ratio < 0 ? Gravity.LEFT : Gravity.RIGHT; 
  
 Gravity.apply(gravity, // Start cutting from the left or the right  
 w, // Width of the target rectangle  
 h, // The height of the target rectangle  
 bounds, // The original rectangle cut out  
 r); // Target rectangle -- the rectangular area required in the final canvas   
  
 // Save the prototype of the canvas  
                canvas.save();
 //Cut out a part of the canvas  
                canvas.clipRect(r);
                mUnSelectedDrawable.draw(canvas);
 // Restore the canvas  
                canvas.restore();
 }
 { // 2. Cut out the right part of the rectangle from the colored image  
 //level:0~5000~10000  
 float ratio = (level / 5000f) - 1f;
 int w = bounds.width();
                w -= ( int ) (w * Math.abs(ratio));
 int h = bounds.height();
 int gravity = ratio < 0 ? Gravity.RIGHT : Gravity.LEFT; 
  
 Gravity.apply(gravity, // Start cutting from the left or the right  
 w, // Width of the target rectangle  
 h, // The height of the target rectangle  
 bounds, // The original rectangle cut out  
 r); // Target rectangle -- the rectangular area required in the final canvas   
  
 // Save the prototype of the canvas  
                canvas.save();
 //Cut out a part of the canvas  
                canvas.clipRect(r);
                mSelectedDrawable.draw(canvas);
 // Restore the canvas  
                canvas.restore();
 }
 }
 } 
      
 @Override  
 protected   boolean onLevelChange( int level) {
 // Sense the call of setLevel and refresh -- draw()  
 invalidateSelf();
 return   true ;
 } 
  
 /**
 * Initialize data
 */  
 @Override  
 protected   void onBoundsChange(Rect bounds) {
 // Define the width and height of two Drawable images -- bound boundaries  
        mUnSelectedDrawable.setBounds(bounds);
        mSelectedDrawable.setBounds(bounds);
 super .onBoundsChange(bounds);
 } 
  
 /**
 * Get the actual width and height of the Drawable
 */  
 @Override  
 public   int getIntrinsicWidth() {
 return mSelectedDrawable.getIntrinsicWidth();
 } 
  
 @Override  
 public   int getIntrinsicHeight() {
 return mSelectedDrawable.getIntrinsicHeight();
 } 
  
 @Override  
 public   void setAlpha( int alpha) { 
  
 } 
  
 @Override  
 public   void setColorFilter(ColorFilter cf) { 
  
 } 
  
 @Override  
 public   int getOpacity() {
 return   0 ;
 } 
  
 }