Android Open Source - Android-Universal-Image-Loader View Aware

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The source code is released under:

Apache License

Java Source Code

/*******************************************************************************
 * Copyright 2014 Sergey Tarasevich/*from   w  w w  .  j a  v a 2 s.c o  m*/
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 * http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 *******************************************************************************/
package com.nostra13.universalimageloader.core.imageaware;

import android.graphics.Bitmap;
import android.graphics.drawable.Drawable;
import android.os.Looper;
import android.view.View;
import android.view.ViewGroup;
import com.nostra13.universalimageloader.core.assist.ViewScaleType;
import com.nostra13.universalimageloader.utils.L;

import java.lang.ref.Reference;
import java.lang.ref.WeakReference;

/**
 * Wrapper for Android {@link android.view.View View}. Keeps weak reference of View to prevent memory leaks.
 *
 * @author Sergey Tarasevich (nostra13[at]gmail[dot]com)
 * @since 1.9.2
 */
public abstract class ViewAware implements ImageAware {

  public static final String WARN_CANT_SET_DRAWABLE = "Can't set a drawable into view. You should call ImageLoader on UI thread for it.";
  public static final String WARN_CANT_SET_BITMAP = "Can't set a bitmap into view. You should call ImageLoader on UI thread for it.";

  protected Reference<View> viewRef;
  protected boolean checkActualViewSize;

  /**
   * Constructor. <br />
   * References {@link #ViewAware(android.view.View, boolean) ImageViewAware(imageView, true)}.
   *
   * @param view {@link android.view.View View} to work with
   */
  public ViewAware(View view) {
    this(view, true);
  }

  /**
   * Constructor
   *
   * @param view                {@link android.view.View View} to work with
   * @param checkActualViewSize <b>true</b> - then {@link #getWidth()} and {@link #getHeight()} will check actual
   *                            size of View. It can cause known issues like
   *                            <a href="https://github.com/nostra13/Android-Universal-Image-Loader/issues/376">this</a>.
   *                            But it helps to save memory because memory cache keeps bitmaps of actual (less in
   *                            general) size.
   *                            <p/>
   *                            <b>false</b> - then {@link #getWidth()} and {@link #getHeight()} will <b>NOT</b>
   *                            consider actual size of View, just layout parameters. <br /> If you set 'false'
   *                            it's recommended 'android:layout_width' and 'android:layout_height' (or
   *                            'android:maxWidth' and 'android:maxHeight') are set with concrete values. It helps to
   *                            save memory.
   */
  public ViewAware(View view, boolean checkActualViewSize) {
    if (view == null) throw new IllegalArgumentException("view must not be null");

    this.viewRef = new WeakReference<View>(view);
    this.checkActualViewSize = checkActualViewSize;
  }

  /**
   * {@inheritDoc}
   * <p/>
   * Width is defined by target {@link android.view.View view} parameters, configuration
   * parameters or device display dimensions.<br />
   * Size computing algorithm (go by steps until get non-zero value):<br />
   * 1) Get the actual drawn <b>getWidth()</b> of the View<br />
   * 2) Get <b>layout_width</b>
   */
  @Override
  public int getWidth() {
    View view = viewRef.get();
    if (view != null) {
      final ViewGroup.LayoutParams params = view.getLayoutParams();
      int width = 0;
      if (checkActualViewSize && params != null && params.width != ViewGroup.LayoutParams.WRAP_CONTENT) {
        width = view.getWidth(); // Get actual image width
      }
      if (width <= 0 && params != null) width = params.width; // Get layout width parameter
      return width;
    }
    return 0;
  }

  /**
   * {@inheritDoc}
   * <p/>
   * Height is defined by target {@link android.view.View view} parameters, configuration
   * parameters or device display dimensions.<br />
   * Size computing algorithm (go by steps until get non-zero value):<br />
   * 1) Get the actual drawn <b>getHeight()</b> of the View<br />
   * 2) Get <b>layout_height</b>
   */
  @Override
  public int getHeight() {
    View view = viewRef.get();
    if (view != null) {
      final ViewGroup.LayoutParams params = view.getLayoutParams();
      int height = 0;
      if (checkActualViewSize && params != null && params.height != ViewGroup.LayoutParams.WRAP_CONTENT) {
        height = view.getHeight(); // Get actual image height
      }
      if (height <= 0 && params != null) height = params.height; // Get layout height parameter
      return height;
    }
    return 0;
  }

  @Override
  public ViewScaleType getScaleType() {
    return ViewScaleType.CROP;
  }

  @Override
  public View getWrappedView() {
    return viewRef.get();
  }

  @Override
  public boolean isCollected() {
    return viewRef.get() == null;
  }

  @Override
  public int getId() {
    View view = viewRef.get();
    return view == null ? super.hashCode() : view.hashCode();
  }

  @Override
  public boolean setImageDrawable(Drawable drawable) {
    if (Looper.myLooper() == Looper.getMainLooper()) {
      View view = viewRef.get();
      if (view != null) {
        setImageDrawableInto(drawable, view);
        return true;
      }
    } else {
      L.w(WARN_CANT_SET_DRAWABLE);
    }
    return false;
  }

  @Override
  public boolean setImageBitmap(Bitmap bitmap) {
    if (Looper.myLooper() == Looper.getMainLooper()) {
      View view = viewRef.get();
      if (view != null) {
        setImageBitmapInto(bitmap, view);
        return true;
      }
    } else {
      L.w(WARN_CANT_SET_BITMAP);
    }
    return false;
  }

  /**
   * Should set drawable into incoming view. Incoming view is guaranteed not null.<br />
   * This method is called on UI thread.
   */
  protected abstract void setImageDrawableInto(Drawable drawable, View view);

  /**
   * Should set Bitmap into incoming view. Incoming view is guaranteed not null.< br />
   * This method is called on UI thread.
   */
  protected abstract void setImageBitmapInto(Bitmap bitmap, View view);
}

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