android ListView实现圆角

最新推荐文章于 2021-11-25 17:19:07 发布

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本文介绍了解决Android中ListView项选中状态时顶部和底部圆角丢失的问题，提供了五种不同的实现方法，包括自定义ListView、使用不同选择器资源及自定义绘制等技术手段。

方法一：定义

 
   1<?xml version ="1.0" encoding ="UTF-8" ?>  
 
   2<shape xmlns:android ="http://schemas.android.com/apk/res/android" android:shape ="rectangle" >  
 
   3       <gradient android:startColor ="#B0BCCD" android:endColor ="#6D84A2" android:angle ="270" />  
 
   4       <corners android:bottomRightRadius  ="8dp" android:bottomLeftRadius ="8dp"  android:topLeftRadius ="8dp" 
 
   5              android:topRightRadius ="8dp"  />  
 
   6  
 
   7</shape>

布局文件中的ListView属性android:listSelector="@drawable/shape"

存在问题是，ListView最上面或者最下面的item选中时，圆角背景变成直角的

方法二：修改选中item

 
   01public  class RoundedRectListView extends ListView {    
 
   02        private Context mContext;  
 
   03        public RoundedRectListView( Context context) {  
 
   04                super ( context) ;          
 
   05                this .mContext = context;  
 
   06                init( ) ;  
 
   07        }  
 
   08        public RoundedRectListView( Context context, AttributeSet attrs) {  
 
   09                super ( context, attrs) ;  
 
   10                this .mContext = context;  
 
   11                init( ) ;  
 
   12        }  
 
   13        public RoundedRectListView( Context context, AttributeSet attrs, int defStyle) {  
 
   14                super ( context, attrs, defStyle) ;  
 
   15                this .mContext = context;  
 
   16                init( ) ;  
 
   17        }  
 
   18        protected void init( ) {   
 
   19                setBackgroundDrawable( mContext.getResources ( ) .getDrawable ( R.drawable .background_rounded_white ) ) ;  
 
   20                setCacheColorHint( Color .WHITE ) ;  
 
   21                setFooterDividersEnabled( false ) ;   
 
   22        }  
 
   23        @Override
 
   24        public boolean onInterceptTouchEvent( MotionEvent ev) {  
 
   25   
 
   26                switch ( ev.getAction ( ) ) {  
 
   27                case MotionEvent.ACTION_DOWN :  
 
   28                        int x = ( int  ) ev.getX ( ) ;  
 
   29                        int y = ( int  ) ev.getY ( ) ;  
 
   30                        int itemnum = pointToPosition( x, y) ;  
 
   31                        if ( itemnum == AdapterView.INVALID_POSITION )  
 
   32                                break ;                    
 
   33                        else 
 
   34                        {   
 
   35                                if ( itemnum== 0) {  
 
   36                                        if ( itemnum== ( getAdapter( ) .getCount ( ) - 1) )  
 
   37                                                setSelector( R.drawable .listview_selection_shade_rounded ) ;  
 
   38                                        else 
 
   39                                                setSelector( R.drawable .listview_selection_shade_top_rounded ) ;  
 
   40                                }  
 
   41                                else if ( itemnum== ( getAdapter( ) .getCount ( ) - 1) )  
 
   42                                        setSelector( R.drawable .listview_selection_shade_bottom_rounded ) ;  
 
   43                                else 
 
   44                                        setSelector( R.drawable .listview_selection_shade ) ;                        
 
   45                        }  
 
   46                        break ;  
 
   47                case MotionEvent.ACTION_UP :  
 
   48                        break ;  
 
   49                }  
 
   50                return true ;      
 
   51        }        
 
   52}

方法三：定义selector

 
   01public  class RoundedRectListView extends ListView {      
 
   02        private Context mContext;  
 
   03   
 
   04        public RoundedRectListView( Context context) {  
 
   05                super ( context) ;          
 
   06                this .mContext = context;  
 
   07                init( ) ;  
 
   08        }  
 
   09        public RoundedRectListView( Context context, AttributeSet attrs) {  
 
   10                super ( context, attrs) ;  
 
   11                this .mContext = context;  
 
   12                init( ) ;  
 
   13        }  
 
   14        public RoundedRectListView( Context context, AttributeSet attrs, int defStyle) {  
 
   15                super ( context, attrs, defStyle) ;  
 
   16                this .mContext = context;  
 
   17                init( ) ;  
 
   18        }  
 
   19        protected void init( ) {   
 
   20                setBackgroundDrawable( mContext.getResources ( ) .getDrawable ( R.drawable .background_rounded_white ) ) ;  
 
   21                setCacheColorHint( Color .WHITE ) ;  
 
   22                setFooterDividersEnabled( false ) ;   
 
   23        }  
 
   24        @Override
 
   25        public boolean onInterceptTouchEvent( MotionEvent ev) {  
 
   26   
 
   27                switch ( ev.getAction ( ) ) {  
 
   28                case MotionEvent.ACTION_DOWN :  
 
   29                        int x = ( int  ) ev.getX ( ) ;  
 
   30                        int y = ( int  ) ev.getY ( ) ;  
 
   31                        int itemnum = pointToPosition( x, y) ;  
 
   32   
 
   33                        if ( itemnum == AdapterView.INVALID_POSITION )  
 
   34                                break ;                    
 
   35                        else 
 
   36                        {   
 
   37                                if ( itemnum== 0) {  
 
   38                                        if ( itemnum== ( getAdapter( ) .getCount ( ) - 1) )  
 
   39                                                setSelector( R.drawable .listview_selection_shade_rounded ) ;  
 
   40                                        else 
 
   41                                                setSelector( R.drawable .listview_selection_shade_top_rounded ) ;  
 
   42                                }  
 
   43                                else if ( itemnum== ( getAdapter( ) .getCount ( ) - 1) )  
 
   44                                        setSelector( R.drawable .listview_selection_shade_bottom_rounded ) ;  
 
   45                                else 
 
   46                                        setSelector( R.drawable .listview_selection_shade ) ;                        
 
   47                        }  
 
   48                        break ;  
 
   49                case MotionEvent.ACTION_UP :  
 
   50                        break ;  
 
   51                }  
 
   52                return true ;      
 
   53        }        
 
   54}

方法四：方法二和方法三的结合

 
   001public  class RoundedRectListView extends ListView {    
 
   002  
 
   003        private Context mContext;  
 
   004   
 
   005        public RoundedRectListView( Context context) {  
 
   006                super ( context) ;          
 
   007                this .mContext = context;  
 
   008                init( ) ;  
 
   009        }  
 
   010        public RoundedRectListView( Context context, AttributeSet attrs) {  
 
   011                super ( context, attrs) ;  
 
   012                this .mContext = context;  
 
   013                init( ) ;  
 
   014        }  
 
   015        public RoundedRectListView( Context context, AttributeSet attrs, int defStyle) {  
 
   016                super ( context, attrs, defStyle) ;  
 
   017                this .mContext = context;  
 
   018                init( ) ;  
 
   019        }  
 
   020       protected void init( ) {   
 
   021                setBackgroundDrawable( mContext.getResources ( ) .getDrawable ( R.drawable .background_rounded_white ) ) ;  
 
   022                setCacheColorHint( Color .WHITE ) ;  
 
   023                setFooterDividersEnabled( false ) ;          
 
   024                setSelector( new Selector( RoundedRectListView.this ,- 1) ) ;  
 
   025        }  
 
   026   @Override
 
   027        public boolean onInterceptTouchEvent( MotionEvent ev) {  
 
   028                switch ( ev.getAction ( ) ) {  
 
   029                case MotionEvent.ACTION_DOWN :  
 
   030                        int x = ( int  ) ev.getX ( ) ;  
 
   031                        int y = ( int  ) ev.getY ( ) ;  
 
   032                        int itemnum = pointToPosition( x, y) ;  
 
   033                        if ( itemnum == AdapterView.INVALID_POSITION )  
 
   034                                break ;                    
 
   035                        else 
 
   036                        {                
 
   037                           setSelector( new Selector( RoundedRectListView.this ,itemnum) ) ;                  
 
   038                        }  
 
   039                        break ;  
 
   040                case MotionEvent.ACTION_UP :  
 
   041                        break ;  
 
   042                }  
 
   043                return true ;      
 
   044        }  
 
   045    class Selector extends Drawable {  
 
   046        private static final  String TAG = "Selector"  ;  
 
   047        private Paint mPaint;  
 
   048        private AdapterView mList;  
 
   049        private RectF mRectF;  
 
   050        private int position;   
 
   051          
 
   052        public Selector( AdapterView list,int position) {  
 
   053            mList = list;  
 
   054            mPaint = new Paint ( ) ;  
 
   055            mRectF = new RectF( ) ;  
 
   056            this .position = position  
 
   057  
 
   058            LinearGradient g= new LinearGradient( mRectF.top ,mRectF.left ,mRectF.right ,mRectF.bottom ,Color .parseColor ( "#058cf5" ) ,Color .parseColor ( "#015fe6" ) ,TileMode.REPEAT ) ;    
 
   059  
 
   060    mPaint.setShader ( g) ;  
 
   061        }  
 
   062        @Override
 
   063        public void draw( Canvas canvas) {  
 
   064            Rect b = getBounds( ) ;  
 
   065            int mPosition = mList.getSelectedItemPosition ( ) ;   
 
   066            if ( mPosition==- 1) {  
 
   067                mPosition= position;  
 
   068            }  
 
   069            Log.d ( TAG, "Position :" + mPosition) ;  
 
   070            canvas.save ( ) ;  
 
   071            canvas.clipRect ( b.left , b.top , b.right , ( b.bottom + b.top ) / 2) ;  
 
   072            drawHalf( canvas, b, mPosition == 0) ;  
 
   073            canvas.restore ( ) ;  
 
   074            canvas.save ( ) ;  
 
   075            canvas.clipRect ( b.left , ( b.bottom + b.top ) / 2, b.right , b.bottom ) ;  
 
   076            drawHalf( canvas, b, mPosition == mList.getAdapter ( ) .getCount ( ) - 1 && b.bottom == mList.getHeight ( ) ) ;  
 
   077            canvas.restore ( ) ;  
 
   078            Log.d ( TAG, "draw " + b) ;   
 
   079        }  
 
   080        private void drawHalf( Canvas canvas, Rect b ,boolean round) {            
 
   081                  
 
   082            if ( round) {  
 
   083                mRectF.set ( b) ;  
 
   084                canvas.drawRoundRect ( mRectF, 10, 10, mPaint) ;                
 
   085            } else {   
 
   086                canvas.drawRect ( b, mPaint) ;                
 
   087            }  
 
   088        }  
 
   089        @Override
 
   090        public int getOpacity( ) {   
 
   091            return 0 ;  
 
   092        }  
 
   093        @Override
 
   094        public void setAlpha(  int alpha) {  
 
   095        }  
 
   096        @Override
 
   097        public void setColorFilter( ColorFilter cf) {  
 
   098        }  
 
   099    }   
 
   100}

方法五：

 
   01public  class RoundedRectListView extends ListView {  
 
   02    private static final  float RADIUS = 16 ;  
 
   03    private Path mClip;  
 
   04    public RoundedRectListView( Context context, AttributeSet attrs) {  
 
   05        super ( context, attrs) ;  
 
   06        init( ) ;  
 
   07    }   
 
   08    private void init( ) {   
 
   09        GradientDrawable gd = new GradientDrawable( ) ;  
 
   10        gd.setCornerRadius ( RADIUS) ;  
 
   11        gd.setColor ( 0xff208020) ;   
 
   12        setBackgroundDrawable( gd) ;  
 
   13        setCacheColorHint( 0) ;  
 
   14        setVerticalFadingEdgeEnabled( false ) ;   
 
   15        StateListDrawable sld = new StateListDrawable( ) ;  
 
   16        sld.addState (  
 
   17                PRESSED_ENABLED_STATE_SET,  
 
   18                new GradientDrawable( Orientation.LEFT_RIGHT , new int [ ] { 0xffa58cf5, 0xffa13f99} ) ) ;  
 
   19        sld.addState (  
 
   20                EMPTY_STATE_SET, 
 
   21                new GradientDrawable( Orientation.LEFT_RIGHT , new int [ ] { 0xff058cf5, 0xff013f99} ) ) ;  
 
   22        setSelector( sld) ;  
 
   23    }   
 
   24    @Override
 
   25    protected void onSizeChanged(  int w, int h, int  oldw, int oldh) {  
 
   26        super .onSizeChanged ( w, h, oldw, oldh) ;  
 
   27        mClip = new Path( ) ;   
 
   28        RectF rect = new RectF(  0, 0, w, h) ;  
 
   29        mClip.addRoundRect ( rect, RADIUS, RADIUS, Direction.CW ) ;  
 
   30    }   
 
   31   @Override
 
   32    protected void dispatchDraw( Canvas canvas) {  
 
   33        canvas.save ( ) ;  
 
   34        canvas.clipPath ( mClip) ;  
 
   35        super .dispatchDraw ( canvas) ;  
 
   36        canvas.restore ( ) ;  
 
   37    }   
 
   38}