圖片加載進度 自定義ImageView

首先聲明：這個是看了一個哥們前兩天發的博客，覺得比較有意思，就模仿着寫了一遍，這裏就當作自己的學習記錄了。

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);  //調用父類畫Image

		paint.setColor(Color.parseColor(TRANSLUCENT));//在ImageView 上覆蓋半透明
		canvas.drawRect(0, 0, getWidth(), getHeight() - getHeight() * progress
				/ 100, paint);//相對自身來說(0, 0)就是ImageView的左上角
		
		paint.setColor(Color.parseColor(TRANSPARENT)); //接着在getHeight() * progress / 100把已經加載的進度的部分覆蓋透明
		canvas.drawRect(0, 0, getWidth(), getHeight() * progress / 100, paint);

		paint.setColor(Color.parseColor(WHITE));    //在圖片上繪製加載的百分比
		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;
	}
}