安卓简单的底部导航栏｛特别简单的框架｝ _底部导航

【安卓简单的底部导航栏｛特别简单的框架｝】业无高卑志当坚，男儿有求安得闲？这篇文章主要讲述安卓简单的底部导航栏｛特别简单的框架｝相关的知识，希望能为你提供帮助。
转 github https://github.com/xubinhong/BottomBar 不知道是哪位大佬写的太他妈牛逼了
他自己封装了一个bottombar类你用的时候就把他那个类复制到你的java文件夹下 xml文件写相应的包名加类名就行
各种图标下载地址 https://www.iconfont.cn/ 马云的东西各行业都有真行！
截图如下

文章图片

package com.stdu.x5.utils; import android.annotation.SuppressLint; import android.content.Context; import android.graphics.Bitmap; import android.graphics.Canvas; import android.graphics.Color; import android.graphics.Paint; import android.graphics.Rect; import android.graphics.drawable.BitmapDrawable; import android.util.AttributeSet; import android.view.MotionEvent; import android.view.View; import java.util.ArrayList; import java.util.List; import androidx.annotation.Nullable; import androidx.appcompat.app.AppCompatActivity; import androidx.fragment.app.Fragment; import androidx.fragment.app.FragmentTransaction; public class BottomBar extends View {private Context context; public BottomBar(Context context, @Nullable AttributeSet attrs) { super(context, attrs); this.context = context; }////////////////////////////////////////////////// //提供的api 并且根据api做一定的物理基础准备 //////////////////////////////////////////////////private int containerId; private List< Class> fragmentClassList = new ArrayList< > (); private List< String> titleList = new ArrayList< > (); private List< Integer> iconResBeforeList = new ArrayList< > (); private List< Integer> iconResAfterList = new ArrayList< > (); private List< Fragment> fragmentList = new ArrayList< > (); private int itemCount; private Paint paint = new Paint(); private List< Bitmap> iconBitmapBeforeList = new ArrayList< > (); private List< Bitmap> iconBitmapAfterList = new ArrayList< > (); private List< Rect> iconRectList = new ArrayList< > (); private int currentCheckedIndex; private int firstCheckedIndex; private int titleColorBefore = Color.parseColor("#999999"); private int titleColorAfter = Color.parseColor("#ff5d5e"); private int titleSizeInDp = 13; //这里是字体大小 private int iconWidth = 26; //icon大小 private int iconHeight = 26; //icon大小 private int titleIconMargin = -1; //文字距离底部距离public BottomBar setContainer(int containerId) { this.containerId = containerId; return this; }public BottomBar setTitleBeforeAndAfterColor(String beforeResCode, String AfterResCode) {//支持"#333333"这种形式 titleColorBefore = Color.parseColor(beforeResCode); titleColorAfter = Color.parseColor(AfterResCode); return this; }public BottomBar setTitleSize(int titleSizeInDp) { this.titleSizeInDp = titleSizeInDp; return this; }public BottomBar setIconWidth(int iconWidth) { this.iconWidth = iconWidth; return this; }public BottomBar setTitleIconMargin(int titleIconMargin) { this.titleIconMargin = titleIconMargin; return this; }public BottomBar setIconHeight(int iconHeight) { this.iconHeight = iconHeight; return this; }public BottomBar addItem(Class fragmentClass, String title, int iconResBefore, int iconResAfter) { fragmentClassList.add(fragmentClass); titleList.add(title); iconResBeforeList.add(iconResBefore); iconResAfterList.add(iconResAfter); return this; }public BottomBar setFirstChecked(int firstCheckedIndex) {//从0开始 this.firstCheckedIndex = firstCheckedIndex; return this; }public void build() { itemCount = fragmentClassList.size(); //预创建bitmap的Rect并缓存 //预创建icon的Rect并缓存 for (int i = 0; i < itemCount; i++) { Bitmap beforeBitmap = getBitmap(iconResBeforeList.get(i)); iconBitmapBeforeList.add(beforeBitmap); Bitmap afterBitmap = getBitmap(iconResAfterList.get(i)); iconBitmapAfterList.add(afterBitmap); Rect rect = new Rect(); iconRectList.add(rect); Class clx = fragmentClassList.get(i); try { Fragment fragment = (Fragment) clx.newInstance(); fragmentList.add(fragment); } catch (InstantiationException | IllegalAccessException e) { e.printStackTrace(); } }currentCheckedIndex = firstCheckedIndex; switchFragment(currentCheckedIndex); invalidate(); }private Bitmap getBitmap(int resId) { BitmapDrawable bitmapDrawable = (BitmapDrawable) context.getResources().getDrawable(resId); return bitmapDrawable.getBitmap(); }////////////////////////////////////////////////// //初始化数据基础 //////////////////////////////////////////////////@Override protected void onLayout(boolean changed, int left, int top, int right, int bottom) { super.onLayout(changed, left, top, right, bottom); initParam(); }private int titleBaseLine; private List< Integer> titleXList = new ArrayList< > (); private int parentItemWidth; private void initParam() { if (itemCount != 0) { //单个item宽高 parentItemWidth = getWidth() / itemCount; int parentItemHeight = getHeight(); //图标边长 int iconWidth = dp2px(this.iconWidth); //先指定20dp int iconHeight = dp2px(this.iconHeight); //图标文字margin int textIconMargin = dp2px(((float)titleIconMargin)/2); //先指定5dp，这里除以一半才是正常的margin，不知道为啥，可能是图片的原因//标题高度 int titleSize = dp2px(titleSizeInDp); //这里先指定10dp paint.setTextSize(titleSize); Rect rect = new Rect(); paint.getTextBounds(titleList.get(0), 0, titleList.get(0).length(), rect); int titleHeight = rect.height(); //从而计算得出图标的起始top坐标、文本的baseLine int iconTop = (parentItemHeight - iconHeight - textIconMargin - titleHeight)/2; titleBaseLine = parentItemHeight - iconTop; //对icon的rect的参数进行赋值 int firstRectX = (parentItemWidth - iconWidth) / 2; //第一个icon的左 for (int i = 0; i < itemCount; i++) { int rectX = i * parentItemWidth + firstRectX; Rect temp = iconRectList.get(i); temp.left = rectX; temp.top = iconTop ; temp.right = rectX + iconWidth; temp.bottom = iconTop + iconHeight; }//标题（单位是个问题） for (int i = 0; i < itemCount; i ++) { String title = titleList.get(i); paint.getTextBounds(title, 0, title.length(), rect); titleXList.add((parentItemWidth - rect.width()) / 2 + parentItemWidth * i); } } }private int dp2px(float dpValue) { float scale = context.getResources().getDisplayMetrics().density; return (int) (dpValue * scale + 0.5f); }////////////////////////////////////////////////// //根据得到的参数绘制 //////////////////////////////////////////////////@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); //这里让view自身替我们画背景如果指定的话if (itemCount != 0) { //画背景 paint.setAntiAlias(false); for (int i = 0; i < itemCount; i++) { Bitmap bitmap = null; if (i == currentCheckedIndex) { bitmap = iconBitmapAfterList.get(i); } else { bitmap = iconBitmapBeforeList.get(i); } Rect rect = iconRectList.get(i); canvas.drawBitmap(bitmap, null, rect, paint); //null代表bitmap全部画出 }//画文字 paint.setAntiAlias(true); for (int i = 0; i < itemCount; i ++) { String title = titleList.get(i); if (i == currentCheckedIndex) { paint.setColor(titleColorAfter); } else { paint.setColor(titleColorBefore); } int x = titleXList.get(i); canvas.drawText(title, x, titleBaseLine, paint); } } }////////////////////////////////////////////////// //点击事件:我观察了微博和掌盟，发现down和up都在该区域内才响应 //////////////////////////////////////////////////int target = -1; @SuppressLint("ClickableViewAccessibility") @Override public boolean onTouchEvent(MotionEvent event) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN : target = withinWhichArea((int)event.getX()); break; case MotionEvent.ACTION_UP : if (event.getY() < 0) { break; } if (target == withinWhichArea((int)event.getX())) { //这里触发点击事件 switchFragment(target); currentCheckedIndex = target; invalidate(); } target = -1; break; } return true; //这里return super为什么up执行不到？是因为return super的值，全部取决于你是否 //clickable，当你down事件来临，不可点击，所以return false，也就是说，而且你没 //有设置onTouchListener，并且控件是ENABLE的，所以dispatchTouchEvent的返回值 //也是false，所以在view group的dispatchTransformedTouchEvent也是返回false， //这样一来，view group中的first touch target就是空的，所以intercept标记位 //果断为false，然后就再也进不到循环取孩子的步骤了，直接调用dispatch- // TransformedTouchEvent并传孩子为null，所以直接调用view group自身的dispatch- // TouchEvent了 }private int withinWhichArea(int x) { return x/parentItemWidth; }//从0开始////////////////////////////////////////////////// //碎片处理代码 ////////////////////////////////////////////////// private Fragment currentFragment; //注意这里是只支持AppCompatActivity 需要支持其他老版的自行修改 protected void switchFragment(int whichFragment) { Fragment fragment = fragmentList.get(whichFragment); int frameLayoutId = containerId; if (fragment != null) { FragmentTransaction transaction = ((AppCompatActivity)context).getSupportFragmentManager().beginTransaction(); if (fragment.isAdded()) { if (currentFragment != null) { transaction.hide(currentFragment).show(fragment); } else { transaction.show(fragment); } } else { if (currentFragment != null) { transaction.hide(currentFragment).add(frameLayoutId, fragment); } else { transaction.add(frameLayoutId, fragment); } } currentFragment = fragment; transaction.commit(); } } }

自行理解我反正是没法理解...................