图片加载进度自定义ImageView

最新推荐文章于 2021-05-27 06:10:50 发布

原创最新推荐文章于 2021-05-27 06:10:50 发布 · 947 阅读

0 ·

CC 4.0 BY-SA版权

文章标签：

#imageview #canvas #自定义

android开发专栏收录该内容

25 篇文章

订阅专栏

本文介绍了一个自定义的ImageView类，用于在Android应用中动态显示进度条。通过覆盖onDraw方法，实现了在ImageView上实时更新进度的显示效果。

摘要生成于 C知道，由 DeepSeek-R1 满血版支持，前往体验 >

首先声明：这个是看了一个哥们前两天发的博客，觉得比较有意思，就模仿着写了一遍，这里就当作自己的学习记录了。

package com.jsbtclient.view;

import android.annotation.SuppressLint;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Rect;
import android.util.AttributeSet;
import android.widget.ImageView;

public class ProgressImageView extends ImageView {

	private static final String TRANSLUCENT = "#70000000";
	private static final String TRANSPARENT = "#00000000";
	private static final String WHITE = "#FFFFFF";

	private float textSize = 100;

	private int progress = 0;

	private Paint paint;

	public ProgressImageView(Context context) {
		this(context, null);
	}

	public ProgressImageView(Context context, AttributeSet attrs) {
		super(context, attrs);

		paint = new Paint();
		paint.setAntiAlias(true);
		paint.setStyle(Paint.Style.FILL);

	}

	@SuppressLint("DrawAllocation")
	@Override
	protected void onDraw(Canvas canvas) {
		super.onDraw(canvas);  //调用父类画Image

		paint.setColor(Color.parseColor(TRANSLUCENT));//在ImageView 上覆盖半透明
		canvas.drawRect(0, 0, getWidth(), getHeight() - getHeight() * progress
				/ 100, paint);//相对自身来说(0, 0)就是ImageView的左上角
		
		paint.setColor(Color.parseColor(TRANSPARENT)); //接着在getHeight() * progress / 100把已经加载的进度的部分覆盖透明
		canvas.drawRect(0, 0, getWidth(), getHeight() * progress / 100, paint);

		paint.setColor(Color.parseColor(WHITE));    //在图片上绘制加载的百分比
		paint.setStrokeWidth(2);
		paint.setTextSize(textSize);
		Rect rect = new Rect();
		paint.getTextBounds("100%", 0, "100%".length(), rect);
		canvas.drawText(progress + "%", (getWidth() - rect.width()) / 2,
				getHeight() / 2, paint);
	}

	public void publishProgress(int progress) {
		this.progress = progress;
		invalidate();
	}

	public int getProgress() {
		return progress;
	}

	public float getTextSize() {
		return textSize;
	}

	public void setTextSize(float textSize) {
		this.textSize = textSize;
	}
}