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                        /Android-自定義ViewPager指示器

誰能幫我看一下，我的代碼有什么問題嗎？一直畫不出三角形

public?class?ViewPagerTittleView?extends?LinearLayout?{

????private?static?final?String?TAG?=?"View";
????private?Paint?mPaint;
????private?Path?mPath;
????private?int?mWidth;
????private?int?mHeight;

????private?static?final?float?WIDTH_RADIO?=?1/6f;
????private?int?mInitTransX;
????private?int?mTransX;


????public?ViewPagerTittleView(Context?context)?{
????????this(context,null);
????}

????public?ViewPagerTittleView(Context?context,?AttributeSet?attrs)?{
????????super(context,?attrs);
????????mPaint?=?new?Paint();
????????mPaint.setStyle(Paint.Style.FILL);
????????mPaint.setAntiAlias(true);
????????mPaint.setColor(Color.parseColor("#ffffff"));
????????Log.d("View",?"ViewPagerTittleView:?***********");


????}

????@Override
????protected?void?dispatchDraw(Canvas?canvas)?{
????????canvas.save();
????????canvas.translate(mInitTransX+mTransX,getHeight());
????????canvas.drawPath(mPath,mPaint);
????????canvas.restore();
????????Log.d(TAG?,?"dispatchDraw:?*****");
????????super.dispatchDraw(canvas);

????}

????@Override
????protected?void?onSizeChanged(int?w,?int?h,?int?oldw,?int?oldh)?{
????????super.onSizeChanged(w,?h,?oldw,?oldh);

????????mWidth?=?(int)?(w/3*WIDTH_RADIO);
????????mHeight?=?mWidth/2;
????????mInitTransX?=?w/3/2-mWidth/2;
????????initTriangle();

????????Log.d(TAG,?"onSizeChanged:?********");
????????Log.d(TAG,?"onSizeChanged:?mWidth?=?"+mWidth+"???mInitTranslationX?=?"+mInitTransX+
????????????????"??mHeight?=?"+mHeight);
????}

????/**
?????*?初始化三角形
?????*/
????private?void?initTriangle()?{

????????mPath?=?new?Path();
????????mPath.moveTo(0,0);
????????mPath.lineTo(mWidth,0);
????????mPath.lineTo(mWidth/2,-mHeight);
????????mPath.close();
????????Log.d("View",?"initTriangle:***************?");

????}
}

StorY1ess

2016-05-08

源自：Android-自定義ViewPager指示器 2-3

關(guān)注問題我要回答

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3 回答

AlexSandra
2017-01-21

我的代碼能顯示，你可以對(duì)比下，主要注意下位置是不是設(shè)置得有問題，超出顯示區(qū)域的話是看不到的，還有顏色如果一樣也是看不出來的

import?android.content.Context;
import?android.graphics.Canvas;
import?android.graphics.Color;
import?android.graphics.CornerPathEffect;
import?android.graphics.Paint;
import?android.graphics.Path;
import?android.util.AttributeSet;
import?android.widget.LinearLayout;


public?class?MyViewPagerIndicator?extends?LinearLayout?{

????private?Paint?paint;//畫筆
????private?Path?path;//用Path類型繪制三角形
????private?int?triangleWidth,?triangleHeight;//三角形的寬高
????public?static?final?float?SCALE_TRIANGLE_WIDTH?=?1?/?6f;//寬度為每個(gè)tab寬度的1/6
????private?int?initPositionX,?movePositionX;//初始位置，移動(dòng)的位置


????public?MyViewPagerIndicator(Context?context)?{
????????super(context,?null);
????}

????public?MyViewPagerIndicator(Context?context,?AttributeSet?attrs)?{
????????super(context,?attrs);
????????//初始化畫筆
????????paint?=?new?Paint();
????????paint.setAntiAlias(true);//抗鋸齒
????????paint.setColor(Color.parseColor("#FFF7C533"));
????????paint.setStyle(Paint.Style.FILL);//填充式畫筆
????????paint.setPathEffect(new?CornerPathEffect(3));//設(shè)置ath特效（轉(zhuǎn)角彎曲），這樣畫出來的三角形就不會(huì)太尖銳
????}

????/**
?????*?繪制三角形
?????*/
????@Override
????protected?void?dispatchDraw(Canvas?canvas)?{
????????canvas.save();
????????canvas.translate(initPositionX?+?movePositionX,?getHeight());
????????canvas.drawPath(path,?paint);//arg1被畫的類型，arg2畫筆
????????System.out.println("-------dispatchDraw:init,move,w,h---------"?+?"init:"?+?initPositionX?+?"_move:"?+?movePositionX?+?"_w:"?+?triangleWidth?+?"_h:"?+?triangleHeight);
????????canvas.restore();
????????super.dispatchDraw(canvas);
????}

????/**
?????*?view的size發(fā)生變化時(shí)調(diào)用，可以通過此方法得到view的寬高
?????*/
????@Override
????protected?void?onSizeChanged(int?w,?int?h,?int?oldw,?int?oldh)?{
????????super.onSizeChanged(w,?h,?oldw,?oldh);
????????triangleWidth?=?(int)?(w?/?3?*?SCALE_TRIANGLE_WIDTH);//三角形的寬度
????????triangleHeight?=?triangleWidth?/?2;
????????initPositionX?=?w?/?3?/?2?-?triangleWidth?/?2;//三角形的位置
????????initTriangle();//初始化三角形
????????System.out.println("-------x:initPos---------"?+?initPositionX);
????????System.out.println("-------x:width---------"?+?triangleWidth);
????????System.out.println("-------x:height---------"?+?triangleHeight);
????}

????/**
?????*?初始化三角形
?????*/
????private?void?initTriangle()?{
????????//通過Path構(gòu)造三角形
????????path?=?new?Path();
????????path.moveTo(0,?0);//三角形左下點(diǎn)
????????path.lineTo(triangleWidth,?0);//三角形右下點(diǎn)
????????path.lineTo(triangleWidth?/?2,?-triangleHeight);//三角形上頂點(diǎn)
????????path.close();

????}

}