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在Android开发中通过使用View实现进度条功能？相信很多没有经验的人对此束手无策，为此本文总结了问题出现的原因和解决方法，通过这篇文章希望你能解决这个问题。
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1.ProgressBarView1（支持拖动）：
2.ProgressBarView2（不同进度值显示不同颜色，不支持拖拽）：
代码不多，注释也比较详细，全部贴上了：
（一）ProgressBarView1:
/**
* 自定义绚丽的ProgressBar.
*/
public class ProgressBarView1 extends View {
/**
* 进度条所占用的角度
*/
private static final int ARC_FULL_DEGREE = 300;
/**
* 弧线的宽度
*/
private int STROKE_WIDTH;
/**
* 组件的宽，高
*/
private int width, height;
/**
* 进度条最大值和当前进度值
*/
private float max, progress;
/**
* 是否允许拖动进度条
*/
private boolean draggingEnabled = false;
/**
* 绘制弧线的矩形区域
*/
private RectF circleRectF;
/**
* 绘制弧线的画笔
*/
private Paint progressPaint;
/**
* 绘制文字的画笔
*/
private Paint textPaint;
/**
* 绘制当前进度值的画笔
*/
private Paint thumbPaint;
/**
* 圆弧的半径
*/
private int circleRadius;
/**
* 圆弧圆心位置
*/
private int centerX, centerY;
public ProgressBarView1(Context context) {
super(context);
init();
}
public ProgressBarView1(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public ProgressBarView1(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
progressPaint = new Paint();
progressPaint.setAntiAlias(true);
textPaint = new Paint();
textPaint.setColor(Color.WHITE);
textPaint.setAntiAlias(true);
thumbPaint = new Paint();
thumbPaint.setAntiAlias(true);
//使用自定义字体
textPaint.setTypeface(Typeface.createFromAsset(getContext().getAssets(), "fangz.ttf"));
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (width == 0 || height == 0) {
width = getWidth();
height = getHeight();
//计算圆弧半径和圆心点
circleRadius = Math.min(width, height) / 2;
STROKE_WIDTH = circleRadius / 12;
circleRadius -= STROKE_WIDTH;
centerX = width / 2;
centerY = height / 2;
//圆弧所在矩形区域
circleRectF = new RectF();
circleRectF.left = centerX - circleRadius;
circleRectF.top = centerY - circleRadius;
circleRectF.right = centerX + circleRadius;
circleRectF.bottom = centerY + circleRadius;
}
}
private Rect textBounds = new Rect();
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float start = 90 + ((360 - ARC_FULL_DEGREE) >> 1); //进度条起始点
float sweep1 = ARC_FULL_DEGREE * (progress / max); //进度划过的角度
float sweep2 = ARC_FULL_DEGREE - sweep1; //剩余的角度
//绘制起始位置小圆形
progressPaint.setColor(Color.WHITE);
progressPaint.setStrokeWidth(0);
progressPaint.setStyle(Paint.Style.FILL);
float radians = (float) (((360.0f - ARC_FULL_DEGREE) / 2) / 180 * Math.PI);
float startX = centerX - circleRadius * (float) Math.sin(radians);
float startY = centerY + circleRadius * (float) Math.cos(radians);
canvas.drawCircle(startX, startY, STROKE_WIDTH / 2, progressPaint);
//绘制进度条
progressPaint.setStrokeWidth(STROKE_WIDTH);
progressPaint.setStyle(Paint.Style.STROKE);//设置空心
canvas.drawArc(circleRectF, start, sweep1, false, progressPaint);
//绘制进度条背景
progressPaint.setColor(Color.parseColor("#d64444"));
canvas.drawArc(circleRectF, start + sweep1, sweep2, false, progressPaint);
//绘制结束位置小圆形
progressPaint.setStrokeWidth(0);
progressPaint.setStyle(Paint.Style.FILL);
float endX = centerX + circleRadius * (float) Math.sin(radians);
float endY = centerY + circleRadius * (float) Math.cos(radians);
canvas.drawCircle(endX, endY, STROKE_WIDTH / 2, progressPaint);
//上一行文字
textPaint.setTextSize(circleRadius >> 1);
String text = (int) (100 * progress / max) + "";
float textLen = textPaint.measureText(text);
//计算文字高度
textPaint.getTextBounds("8", 0, 1, textBounds);
float h2 = textBounds.height();
//% 前面的数字水平居中，适当调整
float extra = text.startsWith("1") ? -textPaint.measureText("1") / 2 : 0;
canvas.drawText(text, centerX - textLen / 2 + extra, centerY - 30 + h2 / 2, textPaint);
//百分号
textPaint.setTextSize(circleRadius >> 2);
canvas.drawText("%", centerX + textLen / 2 + extra + 5, centerY - 30 + h2 / 2, textPaint);
//下一行文字
textPaint.setTextSize(circleRadius / 5);
text = "可用内存充足";
textLen = textPaint.measureText(text);
textPaint.getTextBounds(text, 0, text.length(), textBounds);
float h3 = textBounds.height();
canvas.drawText(text, centerX - textLen / 2, centerY + h2 / 2 + h3, textPaint);
//绘制进度位置，也可以直接替换成一张图片
float progressRadians = (float) (((360.0f - ARC_FULL_DEGREE) / 2 + sweep1) / 180 * Math.PI);
float thumbX = centerX - circleRadius * (float) Math.sin(progressRadians);
float thumbY = centerY + circleRadius * (float) Math.cos(progressRadians);
thumbPaint.setColor(Color.parseColor("#33d64444"));
canvas.drawCircle(thumbX, thumbY, STROKE_WIDTH * 2.0f, thumbPaint);
thumbPaint.setColor(Color.parseColor("#99d64444"));
canvas.drawCircle(thumbX, thumbY, STROKE_WIDTH * 1.4f, thumbPaint);
thumbPaint.setColor(Color.WHITE);
canvas.drawCircle(thumbX, thumbY, STROKE_WIDTH * 0.8f, thumbPaint);
}
private boolean isDragging = false;
@Override
public boolean onTouchEvent(@NonNull MotionEvent event) {
if (!draggingEnabled) {
return super.onTouchEvent(event);
}
//处理拖动事件
float currentX = event.getX();
float currentY = event.getY();
int action = event.getAction();
switch (action) {
case MotionEvent.ACTION_DOWN:
//判断是否在进度条thumb位置
if (checkOnArc(currentX, currentY)) {
float newProgress = calDegreeByPosition(currentX, currentY) / ARC_FULL_DEGREE * max;
setProgressSync(newProgress);
isDragging = true;
}
break;
case MotionEvent.ACTION_MOVE:
if (isDragging) {
//判断拖动时是否移出去了
if (checkOnArc(currentX, currentY)) {
setProgressSync(calDegreeByPosition(currentX, currentY) / ARC_FULL_DEGREE * max);
} else {
isDragging = false;
}
}
break;
case MotionEvent.ACTION_UP:
isDragging = false;
break;
}
return true;
}
private float calDistance(float x1, float y1, float x2, float y2) {
return (float) Math.sqrt((x1 - x2) * (x1 - x2) + (y1 - y2) * (y1 - y2));
}
/**
* 判断该点是否在弧线上（附近）
*/
private boolean checkOnArc(float currentX, float currentY) {
float distance = calDistance(currentX, currentY, centerX, centerY);
float degree = calDegreeByPosition(currentX, currentY);
return distance > circleRadius - STROKE_WIDTH * 5 && distance < circleRadius + STROKE_WIDTH * 5
&& (degree >= -8 && degree <= ARC_FULL_DEGREE + 8);
}
/**
* 根据当前位置，计算出进度条已经转过的角度。
*/
private float calDegreeByPosition(float currentX, float currentY) {
float a1 = (float) (Math.atan(1.0f * (centerX - currentX) / (currentY - centerY)) / Math.PI * 180);
if (currentY < centerY) {
a1 += 180;
} else if (currentY > centerY && currentX > centerX) {
a1 += 360;
}
return a1 - (360 - ARC_FULL_DEGREE) / 2;
}
public void setMax(int max) {
this.max = max;
invalidate();
}
public void setProgress(float progress) {
final float validProgress = checkProgress(progress);
//动画切换进度值
new Thread(new Runnable() {
@Override
public void run() {
float oldProgress = ProgressBarView1.this.progress;
for (int i = 1; i <= 100; i++) {
ProgressBarView1.this.progress = oldProgress + (validProgress - oldProgress) * (1.0f * i / 100);
postInvalidate();
SystemClock.sleep(20);
}
}
}).start();
}
public void setProgressSync(float progress) {
this.progress = checkProgress(progress);
invalidate();
}
//保证progress的值位于[0,max]
private float checkProgress(float progress) {
if (progress < 0) {
return 0;
}
return progress > max ? max : progress;
}
public void setDraggingEnabled(boolean draggingEnabled) {
this.draggingEnabled = draggingEnabled;
}
}（二）ProgressBarView2:
/**
* 自定义绚丽的ProgressBar.
*/
public class ProgressBarView2 extends View {
/**
* 进度条所占用的角度
*/
private static final int ARC_FULL_DEGREE = 300;
//进度条个数
private static final int COUNT = 100;
//每个进度条所占用角度
private static final float ARC_EACH_PROGRESS = ARC_FULL_DEGREE * 1.0f / (COUNT - 1);
/**
* 弧线细线条的长度
*/
private int ARC_LINE_LENGTH;
/**
* 弧线细线条的宽度
*/
private int ARC_LINE_WIDTH;
/**
* 组件的宽，高
*/
private int width, height;
/**
* 进度条最大值和当前进度值
*/
private float max, progress;
/**
* 绘制弧线的画笔
*/
private Paint progressPaint;
/**
* 绘制文字的画笔
*/
private Paint textPaint;
/**
* 绘制文字背景圆形的画笔
*/
private Paint textBgPaint;
/**
* 圆弧的半径
*/
private int circleRadius;
/**
* 圆弧圆心位置
*/
private int centerX, centerY;
public ProgressBarView2(Context context) {
super(context);
init();
}
public ProgressBarView2(Context context, AttributeSet attrs) {
super(context, attrs);
init();
}
public ProgressBarView2(Context context, AttributeSet attrs, int defStyleAttr) {
super(context, attrs, defStyleAttr);
init();
}
private void init() {
progressPaint = new Paint();
progressPaint.setAntiAlias(true);
textPaint = new Paint();
textPaint.setColor(Color.WHITE);
textPaint.setAntiAlias(true);
textBgPaint = new Paint();
textBgPaint.setAntiAlias(true);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
if (width == 0 || height == 0) {
width = getWidth();
height = getHeight();
//计算圆弧半径和圆心点
circleRadius = Math.min(width, height) / 2;
ARC_LINE_LENGTH = circleRadius / 6;
ARC_LINE_WIDTH = ARC_LINE_LENGTH / 8;
centerX = width / 2;
centerY = height / 2;
}
}
private Rect textBounds = new Rect();
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
float start = (360 - ARC_FULL_DEGREE) >> 1; //进度条起始角度
float sweep1 = ARC_FULL_DEGREE * (progress / max); //进度划过的角度
//绘制进度条
progressPaint.setColor(Color.parseColor(calColor(progress / max, "#ffff0000", "#ff00ff00")));
progressPaint.setStrokeWidth(ARC_LINE_WIDTH);
float drawDegree = 1.6f;
while (drawDegree <= ARC_FULL_DEGREE) {
double a = (start + drawDegree) / 180 * Math.PI;
float lineStartX = centerX - circleRadius * (float) Math.sin(a);
float lineStartY = centerY + circleRadius * (float) Math.cos(a);
float lineStopX = lineStartX + ARC_LINE_LENGTH * (float) Math.sin(a);
float lineStopY = lineStartY - ARC_LINE_LENGTH * (float) Math.cos(a);
if (drawDegree > sweep1) {
//绘制进度条背景
progressPaint.setColor(Color.parseColor("#88aaaaaa"));
progressPaint.setStrokeWidth(ARC_LINE_WIDTH >> 1);
}
canvas.drawLine(lineStartX, lineStartY, lineStopX, lineStopY, progressPaint);
drawDegree += ARC_EACH_PROGRESS;
}
//绘制文字背景圆形
textBgPaint.setStyle(Paint.Style.FILL);//设置填充
textBgPaint.setColor(Color.parseColor("#41668b"));
canvas.drawCircle(centerX, centerY, (circleRadius - ARC_LINE_LENGTH) * 0.8f, textBgPaint);
textBgPaint.setStyle(Paint.Style.STROKE);//设置空心
textBgPaint.setStrokeWidth(2);
textBgPaint.setColor(Color.parseColor("#aaaaaaaa"));
canvas.drawCircle(centerX, centerY, (circleRadius - ARC_LINE_LENGTH) * 0.8f, textBgPaint);
//上一行文字
textPaint.setTextSize(circleRadius >> 1);
String text = (int) (100 * progress / max) + "";
float textLen = textPaint.measureText(text);
//计算文字高度
textPaint.getTextBounds("8", 0, 1, textBounds);
float h2 = textBounds.height();
canvas.drawText(text, centerX - textLen / 2, centerY - circleRadius / 10 + h2 / 2, textPaint);
//分
textPaint.setTextSize(circleRadius >> 3);
textPaint.getTextBounds("分", 0, 1, textBounds);
float h21 = textBounds.height();
canvas.drawText("分", centerX + textLen / 2 + 5, centerY - circleRadius / 10 + h2 / 2 - (h2 - h21), textPaint);
//下一行文字
textPaint.setTextSize(circleRadius / 6);
text = "点击优化";
textLen = textPaint.measureText(text);
canvas.drawText(text, centerX - textLen / 2, centerY + circleRadius / 2.5f, textPaint);
}
public void setMax(int max) {
this.max = max;
invalidate();
}
//动画切换进度值(异步)
public void setProgress(final float progress) {
new Thread(new Runnable() {
@Override
public void run() {
float oldProgress = ProgressBarView2.this.progress;
for (int i = 1; i <= 100; i++) {
ProgressBarView2.this.progress = oldProgress + (progress - oldProgress) * (1.0f * i / 100);
postInvalidate();
SystemClock.sleep(20);
}
}
}).start();
}
//直接设置进度值（同步）
public void setProgressSync(float progress) {
this.progress = progress;
invalidate();
}
/**
* 计算渐变效果中间的某个颜色值。
* 仅支持 #aarrggbb 模式,例如 #ccc9c9b2
*/
public String calColor(float fraction, String startValue, String endValue) {
int start_a, start_r, start_g, start_b;
int end_a, end_r, end_g, end_b;
//start
start_a = getIntValue(startValue, 1, 3);
start_r = getIntValue(startValue, 3, 5);
start_g = getIntValue(startValue, 5, 7);
start_b = getIntValue(startValue, 7, 9);
//end
end_a = getIntValue(endValue, 1, 3);
end_r = getIntValue(endValue, 3, 5);
end_g = getIntValue(endValue, 5, 7);
end_b = getIntValue(endValue, 7, 9);
return "#" + getHexString((int) (start_a + fraction * (end_a - start_a)))
+ getHexString((int) (start_r + fraction * (end_r - start_r)))
+ getHexString((int) (start_g + fraction * (end_g - start_g)))
+ getHexString((int) (start_b + fraction * (end_b - start_b)));
}
//从原始#AARRGGBB颜色值中指定位置截取，并转为int.
private int getIntValue(String hexValue, int start, int end) {
return Integer.parseInt(hexValue.substring(start, end), 16);
}
private String getHexString(int value) {
String a = Integer.toHexString(value);
if (a.length() == 1) {
a = "0" + a;
}
return a;
}
}看完上述内容，你们掌握在Android开发中通过使用View实现进度条功能的方法了吗？如果还想学到更多技能或想了解更多相关内容，欢迎关注创新互联行业资讯频道，感谢各位的阅读！