Android图文居中显示控件使用方法详解

2023-07-17 04:00:03 325

最近项目中用到了文字图标的按钮，需要居中显示，如果用TextView实现的方式，必须同时设置padding和drawablePadding。如下：

这种方式需要自己做精确计算。比较麻烦。另外还有一种方式就是用线性布局包裹ImageView和TextView，但这样会增加布局层级。于是自己封装了一个控件DrawableCenterTextView。

attrs.xml文件中定义属性：

对应的Java代码如下：

publicclassDrawableCenterTextViewextendsView{

staticfinalintLEFT=0;
staticfinalintTOP=1;
staticfinalintRIGHT=2;
staticfinalintBOTTOM=3;

privateCharSequencemText;
privateColorStateListmTextColor;
privatefloatmTextSize;
privateintmTextStyle;
privateintmDrawablePadding;
privateDrawable[]mCompoundDrawables;

privateRectmTextBounds;
privateRectmDrawableLeftBounds;
privateRectmDrawableTopBounds;
privateRectmDrawableRightBounds;
privateRectmDrawableBottomBounds;

privateTextPaintmTextPaint;

publicDrawableCenterTextView(Contextcontext){
this(context,null);
}

publicDrawableCenterTextView(Contextcontext,AttributeSetattrs){
this(context,attrs,0);
}

publicDrawableCenterTextView(Contextcontext,AttributeSetattrs,intdefStyleAttr){
super(context,attrs,defStyleAttr);

DrawabledrawableLeft=null,drawableTop=null,drawableRight=null,drawableBottom=null;
TypedArrayta=context.obtainStyledAttributes(attrs,R.styleable.DrawableCenterTextView,defStyleAttr,0);
mText=ta.getText(R.styleable.DrawableCenterTextView_android_text);
mTextColor=ta.getColorStateList(R.styleable.DrawableCenterTextView_android_textColor);
mTextSize=ta.getDimensionPixelSize(R.styleable.DrawableCenterTextView_android_textSize,15);
mTextStyle=ta.getInt(R.styleable.DrawableCenterTextView_android_textStyle,0);

drawableLeft=ta.getDrawable(R.styleable.DrawableCenterTextView_android_drawableLeft);
drawableTop=ta.getDrawable(R.styleable.DrawableCenterTextView_android_drawableTop);
drawableRight=ta.getDrawable(R.styleable.DrawableCenterTextView_android_drawableRight);
drawableBottom=ta.getDrawable(R.styleable.DrawableCenterTextView_android_drawableBottom);

mDrawablePadding=ta.getDimensionPixelSize(R.styleable.DrawableCenterTextView_android_drawablePadding,0);
ta.recycle();

if(mTextColor==null){
mTextColor=ColorStateList.valueOf(0xFF000000);
}

mTextPaint=newTextPaint(Paint.ANTI_ALIAS_FLAG);
mTextPaint.density=getResources().getDisplayMetrics().density;
mTextPaint.setTextSize(mTextSize);
setTypeface(Typeface.create(Typeface.DEFAULT,mTextStyle));

setCompoundDrawablesWithIntrinsicBounds(drawableLeft,drawableTop,drawableRight,drawableBottom);
}

@Override
protectedvoidonMeasure(intwidthMeasureSpec,intheightMeasureSpec){
intwidthMode=MeasureSpec.getMode(widthMeasureSpec);
intheightMode=MeasureSpec.getMode(heightMeasureSpec);
intwidthSize=MeasureSpec.getSize(widthMeasureSpec);
intheightSize=MeasureSpec.getSize(heightMeasureSpec);

intwidth;
intheight;

//计算文本范围
calcTextBounds();

if(widthMode==MeasureSpec.EXACTLY){
width=widthSize;
}else{
width=mTextBounds.width();

if(mCompoundDrawables!=null){
if(mCompoundDrawables[TOP]!=null){
width=Math.max(width,mDrawableTopBounds.width());
}

if(mCompoundDrawables[BOTTOM]!=null){
width=Math.max(width,mDrawableBottomBounds.width());
}

//加上左右内边距及drawable宽度和drawable间距
width+=getCompoundPaddingLeft()+getCompoundPaddingRight();

width=Math.max(width,getSuggestedMinimumWidth());

if(widthMode==MeasureSpec.AT_MOST){
width=Math.min(widthSize,width);
}
}
}

if(heightMode==MeasureSpec.EXACTLY){
height=heightSize;
}else{
height=mTextBounds.height();

if(mCompoundDrawables!=null){
if(mCompoundDrawables[LEFT]!=null){
height=Math.max(height,mDrawableLeftBounds.height());
}

if(mCompoundDrawables[RIGHT]!=null){
height=Math.max(height,mDrawableRightBounds.height());
}

//加上上下内边距及drawable高度和drawable间距
height+=getCompoundPaddingTop()+getCompoundPaddingBottom();

height=Math.max(height,getSuggestedMinimumHeight());

if(heightMode==MeasureSpec.AT_MOST){
height=Math.min(heightSize,height);
}
}
}

setMeasuredDimension(width,height);
}

publicintgetCompoundPaddingTop(){
if(mCompoundDrawables==null||mCompoundDrawables[TOP]==null){
returngetPaddingTop();
}else{
Rectrect=newRect();
mCompoundDrawables[TOP].copyBounds(rect);
returngetPaddingTop()+mDrawablePadding+rect.height();
}
}

publicintgetCompoundPaddingBottom(){
if(mCompoundDrawables==null||mCompoundDrawables[BOTTOM]==null){
returngetPaddingBottom();
}else{
Rectrect=newRect();
mCompoundDrawables[BOTTOM].copyBounds(rect);
returngetPaddingBottom()+mDrawablePadding+rect.height();
}
}

publicintgetCompoundPaddingLeft(){
if(mCompoundDrawables==null||mCompoundDrawables[LEFT]==null){
returngetPaddingLeft();
}else{
Rectrect=newRect();
mCompoundDrawables[LEFT].copyBounds(rect);
returngetPaddingLeft()+mDrawablePadding+rect.width();
}
}

publicintgetCompoundPaddingRight(){
if(mCompoundDrawables==null||mCompoundDrawables[RIGHT]==null){
returngetPaddingRight();
}else{
Rectrect=newRect();
mCompoundDrawables[RIGHT].copyBounds(rect);
returngetPaddingRight()+mDrawablePadding+rect.width();
}
}

@Override
protectedvoidonDraw(Canvascanvas){
super.onDraw(canvas);

intvspace=getBottom()-getTop()-getCompoundPaddingBottom()-getCompoundPaddingTop();//剩余垂直可绘制文本空间大小
inthspace=getRight()-getLeft()-getCompoundPaddingRight()-getCompoundPaddingLeft();//剩余水平可绘制文本空间大小

if(mCompoundDrawables!=null){
if(mCompoundDrawables[LEFT]!=null){
canvas.save();
canvas.translate((hspace-mTextBounds.width())/2.0f+getPaddingLeft(),
getCompoundPaddingTop()+(vspace-mDrawableLeftBounds.height())/2.0f);
mCompoundDrawables[LEFT].draw(canvas);
canvas.restore();
}

if(mCompoundDrawables[RIGHT]!=null){
canvas.save();
canvas.translate(getRight()-getLeft()-getPaddingRight()-(hspace-mTextBounds.width())/2.0f-mDrawableRightBounds.width(),
getCompoundPaddingTop()+(vspace-mDrawableRightBounds.height())/2.0f);
mCompoundDrawables[RIGHT].draw(canvas);
canvas.restore();
}

if(mCompoundDrawables[TOP]!=null){
canvas.save();
canvas.translate(getCompoundPaddingLeft()
+(hspace-mDrawableTopBounds.width())/2.0f,(vspace-mTextBounds.height())/2.0f+getPaddingTop());
mCompoundDrawables[TOP].draw(canvas);
canvas.restore();
}

if(mCompoundDrawables[BOTTOM]!=null){
canvas.save();
canvas.translate(getCompoundPaddingLeft()
+(hspace-mDrawableBottomBounds.width())/2.0f,
getBottom()-getTop()-getPaddingBottom()-(vspace-mTextBounds.height())/2.0f-mDrawableBottomBounds.height());
mCompoundDrawables[BOTTOM].draw(canvas);
canvas.restore();
}
}

if(!TextUtils.isEmpty(mText)){
floatstartX=(hspace-mTextBounds.width())/2.0f+getCompoundPaddingLeft();
//因为drawText以baseline为基准，因此需要向下移ascent
floatstartY=(vspace-mTextBounds.height())/2.0f+getCompoundPaddingTop()-mTextPaint.getFontMetrics().ascent;
mTextPaint.setColor(mTextColor.getColorForState(getDrawableState(),0));
canvas.drawText(mText,0,mText.length(),startX,startY,mTextPaint);
}
}

@Override
protectedvoiddrawableStateChanged(){
super.drawableStateChanged();

if(mTextColor!=null&&mTextColor.isStateful()){
mTextPaint.setColor(mTextColor.getColorForState(getDrawableState(),0));
}

if(mCompoundDrawables!=null){
finalint[]state=getDrawableState();
for(Drawabledr:mCompoundDrawables){
if(dr!=null&&dr.isStateful()&&dr.setState(state)){
invalidateDrawable(dr);
}
}
}
}

publicvoidsetCompoundDrawablesWithIntrinsicBounds(@NullableDrawableleft,
@NullableDrawabletop,@NullableDrawableright,@NullableDrawablebottom){
if(left!=null){
left.setBounds(0,0,left.getIntrinsicWidth(),left.getIntrinsicHeight());
}
if(right!=null){
right.setBounds(0,0,right.getIntrinsicWidth(),right.getIntrinsicHeight());
}
if(top!=null){
top.setBounds(0,0,top.getIntrinsicWidth(),top.getIntrinsicHeight());
}
if(bottom!=null){
bottom.setBounds(0,0,bottom.getIntrinsicWidth(),bottom.getIntrinsicHeight());
}
setCompoundDrawables(left,top,right,bottom);
}

publicvoidsetCompoundDrawables(@NullableDrawableleft,@NullableDrawabletop,
@NullableDrawableright,@NullableDrawablebottom){

if(mCompoundDrawables==null){
mCompoundDrawables=newDrawable[4];
}else{
if(mCompoundDrawables[LEFT]!=null&&mCompoundDrawables[LEFT]!=left){
mCompoundDrawables[LEFT].setCallback(null);
}

if(mCompoundDrawables[TOP]!=null&&mCompoundDrawables[TOP]!=top){
mCompoundDrawables[TOP].setCallback(null);
}

if(mCompoundDrawables[RIGHT]!=null&&mCompoundDrawables[RIGHT]!=right){
mCompoundDrawables[RIGHT].setCallback(null);
}

if(mCompoundDrawables[BOTTOM]!=null&&mCompoundDrawables[BOTTOM]!=bottom){
mCompoundDrawables[BOTTOM].setCallback(null);
}
}

if(left!=null){
mDrawableLeftBounds=newRect();
left.copyBounds(mDrawableLeftBounds);
left.setCallback(this);
mCompoundDrawables[LEFT]=left;
}else{
mCompoundDrawables[LEFT]=null;
}

if(top!=null){
mDrawableTopBounds=newRect();
top.copyBounds(mDrawableTopBounds);
top.setCallback(this);
mCompoundDrawables[TOP]=top;
}else{
mCompoundDrawables[TOP]=null;
}

if(right!=null){
mDrawableRightBounds=newRect();
right.copyBounds(mDrawableRightBounds);
right.setCallback(this);
mCompoundDrawables[RIGHT]=right;
}else{
mCompoundDrawables[RIGHT]=null;
}

if(bottom!=null){
mDrawableBottomBounds=newRect();
bottom.copyBounds(mDrawableBottomBounds);
bottom.setCallback(this);
mCompoundDrawables[BOTTOM]=bottom;
}else{
mCompoundDrawables[BOTTOM]=null;
}

invalidate();
requestLayout();
}

publicvoidsetText(CharSequencetext){
this.mText=text;

invalidate();
requestLayout();
}

publicvoidsetTextSize(floattextSize){
this.mTextSize=TypedValue.applyDimension(TypedValue.COMPLEX_UNIT_SP,textSize,getResources().getDisplayMetrics());

invalidate();
requestLayout();
}

publicvoidsetTextColor(@ColorIntinttextColor){
this.mTextColor=ColorStateList.valueOf(textColor);

invalidate();
}

publicvoidsetTypeface(@NullableTypefacetf){
if(mTextPaint.getTypeface()!=tf){
mTextPaint.setTypeface(tf);

requestLayout();
invalidate();
}
}

privatevoidcalcTextBounds(){
mTextBounds=newRect();

if(TextUtils.isEmpty(mText))return;

if(Build.VERSION.SDK_INT>Build.VERSION_CODES.Q){
mTextPaint.getTextBounds(mText,0,mText.length(),mTextBounds);
}else{
intwidth=(int)Math.ceil(mTextPaint.measureText(mText.toString()));
Paint.FontMetricsfontMetrics=mTextPaint.getFontMetrics();
intheight=(int)Math.ceil(fontMetrics.descent-fontMetrics.ascent);
mTextBounds.set(0,0,width,height);
}
}
}

感谢大家的支持，如有错误请指正。

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Android图文居中显示控件使用方法详解

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