先看效果图
Paste_Image.png
SVID_20170724_102825.gif
从上线的效果图来看， 我们首先不管 移动， 先把柱状绘制出来
- 首先我们定义一些参数
- 柱状的宽度
- 柱状的边距
- 画笔
Paste_Image.png
- 初始化画笔， 宽度 边距
Paste_Image.png
接下来 我们开始绘制 柱状了 从效果图 我们可以看出我们的柱状是这样的形式绘制出来的
Paste_Image.png
<code>
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
/**右边超出的距离-手机之外的宽度*/
mRectDrawWidth=((mRectLeft * mPoints.length) + (mRectSize * mPoints.length + getBrokenLineLeft()-getViewWidth()));
DrawRect(canvas);
}
private void DrawRect(Canvas canvas) {
for (int i = 0; i < mPoints.length; i++) {
Point point = mPoints[i];
Rect rect = new Rect();
int left= (int) ((mRectLeft * i) + (mRectSize * i+ getBrokenLineLeft())-mSlideX);
int right= ((int) ((mRectLeft * i) + (mRectSize * i + mRectSize+ getBrokenLineLeft()-mSlideX)) );
if(left<=getBrokenLineLeft()){
left= (int) getBrokenLineLeft();
}
if(right<=getBrokenLineLeft()){
right= (int) getBrokenLineLeft();
}
rect.left =left;
rect.right =right;
rect.bottom = (int) (getNeedDrawHeight() + getBrokenLineTop());
rect.top = point.y;
canvas.drawRect(rect, mSlideRectPaint);
if(left!=right){
canvas.drawText(i+"",left+((right-left) /2),mPoints[i].y,getBrokenLineTextPaint());
}
}
}
</code>
绘制玩矩阵 接下来移动矩阵 主要是计算mSlideX 保存 这个值
我们这个时候需要重写onTouchEvent 从下面的代码我们可以看出 主要是限制mSlideX 的大小 来限定柱状可以移动的范围 mSlideX<=0的时候 限制向右滑动的距离0 ， mSlideX>=mRectDrawWidth的时候 mSlideX=mRectDrawWidth; 限制左滑的距离 不能超过屏幕之外的矩阵绘制宽度
也就 红线部分的宽度
Paste_Image.png
<code>
private float mSlideX=0;
private float mLastDownX;
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mLastDownX = event.getX();
case MotionEvent.ACTION_UP:
mSlideX += (mLastDownX-event.getX());
mLastDownX = event.getX();
if(mSlideX<=0){
mSlideX=0;
}
if(mSlideX>=mRectDrawWidth){
mSlideX=mRectDrawWidth;
}
postInvalidate();
case MotionEvent.ACTION_MOVE:
mSlideX += (mLastDownX-event.getX());
mLastDownX = event.getX();
if(mSlideX<=0){
mSlideX=0;
}
if(mSlideX>=mRectDrawWidth){
mSlideX=mRectDrawWidth;
}
postInvalidate();
}
return true;
}
</code>
完整代码
<code>
package com.app_chart;
import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Color;
import android.graphics.Paint;
import android.graphics.Point;
import android.graphics.Rect;
import android.support.annotation.Nullable;
import android.util.AttributeSet;
import android.view.MotionEvent;
public class SlideRectChart extends AbsChart {
private static final String TAG = "SlideRectChart";
/**柱子的画笔*/
private Paint mSlideRectPaint;
/**柱子的大小*/
private float mRectSize;
/**柱子之间的边距*/
private float mRectLeft;
/**右边超出的范围*/
private float mRectDrawWidth;
public SlideRectChart(Context context) {
super(context);
init();
}
public SlideRectChart(Context context, @Nullable AttributeSet attrs) {
super(context, attrs);
init();
}
private void init() {
if (mSlideRectPaint == null) {
mSlideRectPaint = new Paint();
}
mSlideRectPaint.setAntiAlias(true);
mSlideRectPaint.setStyle(Paint.Style.FILL);
mSlideRectPaint.setColor(Color.RED);
}
@Override
protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) {
super.onMeasure(widthMeasureSpec, heightMeasureSpec);
mRectSize = getViewWidth() / 24;
mRectLeft = dip2px(4);
}
@Override
protected void onDraw(Canvas canvas) {
super.onDraw(canvas);
/**计算最多移动的距离*/
mRectDrawWidth=((mRectLeft * mPoints.length) + (mRectSize * mPoints.length + getBrokenLineLeft()-getViewWidth()));
DrawRect(canvas);
}
private void DrawRect(Canvas canvas) {
for (int i = 0; i < mPoints.length; i++) {
Point point = mPoints[i];
Rect rect = new Rect();
int left= (int) ((mRectLeft * i) + (mRectSize * i+ getBrokenLineLeft())-mSlideX);
int right= ((int) ((mRectLeft * i) + (mRectSize * i + mRectSize+ getBrokenLineLeft()-mSlideX)) );
if(left<=getBrokenLineLeft()){
left= (int) getBrokenLineLeft();
}
if(right<=getBrokenLineLeft()){
right= (int) getBrokenLineLeft();
}
rect.left =left;
rect.right =right;
rect.bottom = (int) (getNeedDrawHeight() + getBrokenLineTop());
rect.top = point.y;
canvas.drawRect(rect, mSlideRectPaint);
if(left!=right){
canvas.drawText(i+"",left+((right-left) /2),mPoints[i].y,getBrokenLineTextPaint());
}
}
}
private float mSlideX=0;
private float mLastDownX;
@Override
public boolean onTouchEvent(MotionEvent event) {
switch (event.getAction()) {
case MotionEvent.ACTION_DOWN:
mLastDownX = event.getX();
case MotionEvent.ACTION_UP:
mSlideX += (mLastDownX-event.getX());
mLastDownX = event.getX();
if(mSlideX<=0){
mSlideX=0;
}
if(mSlideX>=mRectDrawWidth){
mSlideX=mRectDrawWidth;
}
postInvalidate();
case MotionEvent.ACTION_MOVE:
mSlideX += (mLastDownX-event.getX());
mLastDownX = event.getX();
if(mSlideX<=0){
mSlideX=0;
}
if(mSlideX>=mRectDrawWidth){
mSlideX=mRectDrawWidth;
}
postInvalidate();
}
return true;
}
}
</code>
activity代码
Paste_Image.png
