Android實現梯形TextView效果

第Android實現梯形TextView效果@Override

protectedvoidonLayout(booleanchanged,intleft,inttop,intright,intbottom){

super.onLayout(changed,left,top,right,bottom);

width=getWidth();

height=getHeight();

Log.v(TAG,"widthheight-"+width+""+height);

@Override

protectedvoidonDraw(Canvascanvas){

super.onDraw(canvas);

Log.v(TAG,"onDraw");

if(isLeft){

linePath.moveTo(0+lineOffset,0+lineOffset);

linePath.lineTo(width,0+lineOffset);

linePath.lineTo((int)(width-offsetScale*height),height-lineOffset);

linePath.lineTo(0+lineOffset,height-lineOffset);

linePath.close();

setTextAlignment(TEXT_ALIGNMENT_TEXT_START);

canvas.drawPath(linePath,paint);

canvas.drawText(textContent==null"":textContent,

getPaddingStart()+lineOffset,

height/2+textOffset,textPaint);

}else{

linePath.moveTo(0+lineOffset+offsetScale*height,0+lineOffset);

linePath.lineTo(width-lineOffset,0+lineOffset);

linePath.lineTo(width-lineOffset,height-lineOffset);

linePath.lineTo(0,height-lineOffset);

linePath.close();

setTextAlignment(TEXT_ALIGNMENT_TEXT_END);

canvas.drawPath(linePath,paint);

canvas.drawText(textContent==null"":textContent,

getWidth()-lineOffset-getPaddingEnd()-getDrawTextWidth(textPaint,textContent),

height/2+textOffset,textPaint);

@Override

publicbooleandispatchTouchEvent(MotionEventevent){

if(event.getAction()==MotionEvent.ACTION_DOWN){

if(!isInRegion(event)){//點擊的點的位置不在范圍內則不響應

returnfalse;

returnsuper.dispatchTouchEvent(event);

*判斷點擊的位置是否在要求的范圍內

*@paramevent

*@return

publicbooleanisInRegion(MotionEventevent){

RectFrectF=newRectF();

linePputeBounds(rectF,true);

mRegion.setPath(linePath,newRegion((int)rectF.left,(int)rectF.top,(int)rectF.right,(int)rectF.bottom));

returnmRegion.contains((int)event.getX(),(int)event.getY());

*獲取要畫的字符串的寬度

*@parampaint

*@paramtextContent

*@return

privateintgetDrawTextWidth(Paintpaint,StringtextContent){

floattotalWidth=0f;

if(textContent!=nulltextContent.length()0){

intlen=textContent.length();

float[]widths=newfloat[len];

paint.getTextWidths(textContent,widths);

for(intj=0;jlen;j++){

totalWidth+=widths[j];

return(int)Math.ceil(totalWidth);

*@paramdpValue（DisplayMetrics類中屬性density）

*@return

privateintdp2px(Contextcontext,floatdpValue){

finalfloatscale=context.getResources().getDisplayMetrics().density;

return(int)(dpValue*scale+0.5f);

publicvoidsetTextContent(StringtextContent){

this.textContent=textContent;

invalidate();

publicvoidsetMSelected(booleanisSelected){

textPaint.setColor(isSelectedColor.WHITE:selectedColor);

paint.setStyle(isSelectedPaint.Style.FILL_AND_STROKE:Paint.Style.STROKE);

this.isSelected=isSelected;

invalidate();

@Override

publicbooleanisSelected(){

returnisSelected;

}

要點分析

1.背景與文本內容的繪制

計算好四個點的位置連線，TextView默認的文本內容則設置為空字符串，采用drawText的方式來實現文本的顯示。需要注意的是計算文本的字號長度大小、顏色以及位于整個view的位置、偏移量等。

2.梯形范圍內外的點擊事件處理

依照于設計，梯形內的點擊才有響應，則要計算點擊的位置是否在梯形內，然后通過dispatchTouchEvent來做事件的分發。

*判斷點擊的位置是否在要求的范圍內

*@paramevent

*@return

publicbooleanisInRegion(MotionEventevent){

RectFrectF=newRectF();

linePputeBounds(rectF,true);

mRegion.setPath(linePath,newRegion((int)rectF.left,(int)rectF.top,(int)rectF.right,(int)rectF.bottom));

returnmRegion.contains((int)eve