android实现简单圆弧效果

最近项目完成就开始搞一些有用没用的东西，以前面试的时候有人问我那种圆弧效果怎么做，还问我翻牌效果，我只看过，没有做过，现在有空了，而且想到可能会用到就做个简单的圆弧很简单，自定义个View,创建个Paint，设置 arcPaint.setStyle(Paint.Style.STROKE)再设置圆弧的宽，再在onDraw内调用canvas.drawArc()就好了现在只做一个带刻度的圆弧和一个开口地方是圆角的圆弧。其他各种效果以后再摸索

ArcView.java

public class ArcView extends View { private Paint textPaint; private Paint arcPaint; private Shader backGradient; private Xfermode xfermode; private RectF oval = new RectF(); public ArcView(Context context) { super(context); init(); } public ArcView(Context context, @Nullable AttributeSet attrs) { super(context, attrs); init(); } private int type = 0; public void setType(int type) { this.type = type; if(type == 1){ start = 10; } } private void init(){ arcPaint = new Paint(); arcPaint.setAntiAlias(true); if(type == 0){ xfermode = new PorterDuffXfermode(PorterDuff.Mode.CLEAR); } textPaint = new Paint(); textPaint.setAntiAlias(true); textPaint.setColor(Color.WHITE); textPaint.setTextSize(50); textPaint.setStyle(Paint.Style.FILL); textPaint.setTextAlign(Paint.Align.CENTER); } private int strokeWidth = 40; public void setStrokeWidth(int strokeWidth) { this.strokeWidth = strokeWidth; } private int max = 100; public void setMax(int max) { this.max = max; } private int progress; public void setProgress(int progress) { this.progress = progress; postInvalidate(); } private int start = 0; public void setStart(int start) { if(type == 1){ if(start < 10){start = 10; } }else{ if(start < 0){start = 0; } } this.start = start; } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if(getWidth() != 0){ int width = getWidth(); int height = getHeight(); int cx = width/2; int cy = height/2; if(backGradient == null){oval.set( strokeWidth/2, strokeWidth/2, width - strokeWidth/2, height - strokeWidth/2);int colorStart = getResources().getColor(R.color.colorPrimary);int color2 = Color.GREEN;int colorEnd = Color.RED; backGradient = new SweepGradient(cx,cy,new int[]{color2 ,colorStart, colorEnd},new float[]{0.1f,0.4f,0.9f}); postInvalidate(); }else{int sc = 0;if(type == 0){ sc = canvas.saveLayer(0, 0, canvas.getWidth(), canvas.getHeight(), null, Canvas.ALL_SAVE_FLAG);}else{ canvas.save();} canvas.rotate(90,cx,cy);arcPaint.setColor(Color.GRAY);arcPaint.setStyle(Paint.Style.STROKE);arcPaint.setStrokeWidth(strokeWidth);if(type == 1){ arcPaint.setStrokeCap(Paint.Cap.ROUND);} int s =start;int e = start*2;//底色canvas.drawArc(oval,s,360 - e,false,arcPaint);arcPaint.setShader(backGradient);//渐变int sweep = (int) (progress*1.0f/max*(360 - e));canvas.drawArc(oval,s,sweep,false,arcPaint); arcPaint.setShader(null); if(type == 0){ //刻度 arcPaint.setXfermode(xfermode); arcPaint.setStyle(Paint.Style.STROKE); arcPaint.setStrokeWidth(5); for (int i = 0; i < 36;i++){ canvas.drawLine(0,cy,getWidth(),cy,arcPaint); canvas.rotate(5,cx,cy); } arcPaint.setXfermode(null); canvas.restoreToCount(sc);}else{ canvas.restore();} Paint.FontMetrics fontMetrics = textPaint.getFontMetrics();float top = fontMetrics.top;float bottom = fontMetrics.bottom;int baseLineY = (int) (cy - top/2 - bottom/2);canvas.drawText(progress+'%',cx,baseLineY,textPaint); //十字线，用来参考的，可删除canvas.drawLine(cx,0,cx,height,textPaint);canvas.drawLine(0,cy,width,cy,textPaint); } } }}

activity_main.xml

<?xml version='1.0' encoding='utf-8'?><android.support.constraint.ConstraintLayout xmlns:android='http://schemas.android.com/apk/res/android' xmlns:tools='http://schemas.android.com/tools' android:layout_width='match_parent' android:layout_height='match_parent' tools:context='com.hyq.hm.testdraw.MainActivity'> <LinearLayout android:layout_width='match_parent' android:layout_height='match_parent' android:orientation='vertical' android:gravity='center_horizontal'> <SeekBar android: android:layout_width='match_parent' android:layout_height='wrap_content' android:layout_margin='20dp' android:max='100'/> <LinearLayout android:layout_width='wrap_content' android:layout_height='wrap_content' android:orientation='horizontal'> <com.hyq.hm.testdraw.ArcViewandroid: android:layout_width='100dp'android:layout_height='100dp'android:layout_margin='5dp'android:background='#885453'/> <com.hyq.hm.testdraw.ArcViewandroid: android:layout_width='100dp'android:layout_height='100dp'android:layout_margin='5dp'/> </LinearLayout> </LinearLayout> </android.support.constraint.ConstraintLayout>

MainActivity.java

public class MainActivity extends AppCompatActivity { private SeekBar seekBar; private ArcView arcView0; private ArcView arcView1; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); arcView0 = findViewById(R.id.arc_view_0); arcView1 = findViewById(R.id.arc_view_1); arcView0.setType(0); arcView1.setType(1); arcView0.setStart(10); arcView1.setStart(0); seekBar = findViewById(R.id.seek_bar); seekBar.setOnSeekBarChangeListener(new SeekBar.OnSeekBarChangeListener() { @Override public void onProgressChanged(SeekBar seekBar, int progress, boolean fromUser) {arcView0.setProgress(progress);arcView1.setProgress(progress); } @Override public void onStartTrackingTouch(SeekBar seekBar) { } @Override public void onStopTrackingTouch(SeekBar seekBar) { } }); }}

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