概述
在平时开发过程中经常会碰到需要使用圆角button的情况，一般也会包括很多其他小功能，比如要在里面添加img，设置不同的圆角大小等。
针对这样的场景，直接使用创建多个shape，定义多个xml文件也是可以实现的。但是如果使用非常频繁，那么直接自定义一个就会来的非常方便。
甚至在一些情况下，不是可以用shape定义的规则图形，比如需要用到贝塞尔曲线等。如果全局需要这样风格的view，那么自定义一个View是非常必要的。
本文主要是个demo记录，如有需要的读者可以借鉴学习。
Demo
主要实现功能：
- 自定义圆角大小 支持设置leftDrawable，和自定义文字内容（文字和img默认居中） 支持点击效果
源码
RoundRadiusButton.java
/** * author: xujiajia * description: * 1、drawable只有在设置textString的时候才会生效(居中效果两个一起测量) */public class RoundRadiusButton extends View { //data private int width = 0; private int height = 0; private int roundRadius = 16; private int bgColor = Color.LTGRAY; private boolean isTouching = false; //img and text private Drawable leftDrawable = null; private int drawableWidth = 20; private int drawableHeight = 20; private int leftDrawablePaddingRight = 0; private String textString; private int textSize = 30; private int textColor = Color.BLACK; //onDraw Paint paint; Path path; RectF rectF; Rect rect; public RoundRadiusButton(Context context, int width, int height) { super(context); this.width = width; this.height = height; this.setLayoutParams(new ViewGroup.LayoutParams(width, height)); this.setClickable(true); } public RoundRadiusButton(Context context, AttributeSet attrs) { super(context, attrs); getDataFromAttrs(context, attrs); this.setClickable(true); } public RoundRadiusButton(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); getDataFromAttrs(context, attrs); this.setClickable(true); } private void getDataFromAttrs(Context context, AttributeSet attrs) { if (attrs == null) { return; } TypedArray ta = context.obtainStyledAttributes(attrs, R.styleable.RoundRadiusButton); roundRadius = ta.getDimensionPixelOffset(R.styleable.RoundRadiusButton_roundRadius, 16); bgColor = ta.getColor(R.styleable.RoundRadiusButton_bgColor, Color.LTGRAY); leftDrawable = ta.getDrawable(R.styleable.RoundRadiusButton_leftDrawable); drawableWidth = ta.getDimensionPixelOffset(R.styleable.RoundRadiusButton_drawableWidth, 0); drawableHeight = ta.getDimensionPixelOffset(R.styleable.RoundRadiusButton_drawableHeight, 0); leftDrawablePaddingRight = ta.getDimensionPixelOffset(R.styleable.RoundRadiusButton_leftDrawablePaddingRight, 0); textString = ta.getString(R.styleable.RoundRadiusButton_textString); textSize = ta.getDimensionPixelOffset(R.styleable.RoundRadiusButton_textSize, 0); textColor = ta.getColor(R.styleable.RoundRadiusButton_textColor, Color.BLACK); ta.recycle(); } public void setRoundRadius(int roundRadius) { this.roundRadius = roundRadius; invalidate(); } public void setBgColor(int bgColor) { this.bgColor = bgColor; invalidate(); } public void setLeftDrawable(Drawable leftDrawable, int drawableWidth, int drawableHeight, int paddingRight) { this.leftDrawable = leftDrawable; this.drawableWidth = drawableWidth; this.drawableHeight = drawableHeight; this.leftDrawablePaddingRight = paddingRight; invalidate(); } public void setTextString(String textString) { this.textString = textString; invalidate(); } public void setTextColor(int textColor) { this.textColor = textColor; invalidate(); } public void setTextSize(int textSize) { this.textSize = textSize; invalidate(); } @Override public boolean onTouchEvent(MotionEvent event) { if (isClickable()) { switch (event.getAction()) { case MotionEvent.ACTION_DOWN: isTouching = true; invalidate(); break; case MotionEvent.ACTION_UP: isTouching = false; invalidate(); break; } } return super.onTouchEvent(event); } @Override protected void onDraw(Canvas canvas) { super.onDraw(canvas); if (width == 0 || height == 0) { width = getWidth(); height = getHeight(); } if (paint == null) { paint = new Paint(); } if (path == null) { path = new Path(); } if (rectF == null) { rectF = new RectF(); } if (rect == null) { rect = new Rect(); } paint.setColor(bgColor); paint.setAntiAlias(true);//抗锯齿 paint.setStrokeWidth(0);//线的宽度设为0，避免画圆弧的时候部分圆弧与边界相切 paint.setStyle(Paint.Style.FILL_AND_STROKE); path.setFillType(Path.FillType.WINDING); //左上圆角 path.moveTo(0, roundRadius); rectF.set(0, 0, 2 * roundRadius, 2 * roundRadius); path.addArc(rectF, 180, 90); //上边 path.lineTo(width - roundRadius, 0); //右上圆角 rectF.set(width - roundRadius * 2, 0, width, roundRadius * 2); path.addArc(rectF, -90, 90); //右边 path.lineTo(width, height - roundRadius); //右下圆角 rectF.set(width - roundRadius * 2, height - roundRadius * 2, width, height); path.addArc(rectF, 0, 90); //下边 path.lineTo(roundRadius, height); //左下圆角 rectF.set(0, height - roundRadius * 2, 2 * roundRadius, height); path.addArc(rectF, 90, 90); //左边 path.lineTo(0, roundRadius); path.close(); canvas.drawPath(path, paint); if (isTouching) { paint.setColor(getContext().getResources().getColor(R.color.black_tran_30)); canvas.drawPath(path, paint); } //填充背景中间空白的部分 path.moveTo(0, roundRadius); path.lineTo(width - roundRadius, 0); path.lineTo(width, height - roundRadius); path.lineTo(roundRadius, height); path.close(); canvas.drawPath(path, paint); if (isTouching) { paint.setColor(getContext().getResources().getColor(R.color.black_tran_30)); canvas.drawPath(path, paint); } //text, drawable两个一起计算位置 if (!TextUtils.isEmpty(textString)) { paint.setStrokeWidth(1.5f); paint.setColor(textColor); paint.setTextSize(textSize); rect.setEmpty(); paint.getTextBounds(textString, 0, textString.length(), rect); float leftBitmap = 0; float topBitmap = 0; if (leftDrawable != null) { if (leftDrawable != null) { leftBitmap = (1.0f * width - drawableWidth - rect.width() - leftDrawablePaddingRight) / 2; topBitmap = (1.0f * height - drawableHeight) / 2; leftDrawable.setBounds((int) leftBitmap, (int) topBitmap, (int) (leftBitmap + drawableWidth), (int) (topBitmap + drawableHeight)); leftDrawable.draw(canvas); } } float textX = 0; float textY = 1.0f * height / 2 + paint.getTextSize() / 2 - paint.getFontMetrics().descent / 2; if (leftBitmap == 0 && topBitmap == 0) { textX = width / 2 - rect.width() / 2; } else { textX = leftBitmap + drawableWidth + leftDrawablePaddingRight; } canvas.drawText(textString, textX, textY, paint); } }}
MainActivity.java
public class MainActivity extends AppCompatActivity { private LinearLayout llContainer; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); initView(); } private void initView() { llContainer = findViewById(R.id.ll_container); RoundRadiusButton roundRadiusButton = new RoundRadiusButton(this, 500, 200); roundRadiusButton.setBgColor(Color.LTGRAY); roundRadiusButton.setRoundRadius(40); //text roundRadiusButton.setTextString("testtesttest"); roundRadiusButton.setTextColor(Color.WHITE); roundRadiusButton.setTextSize(40); //drawable roundRadiusButton.setLeftDrawable(getResources().getDrawable(R.mipmap.ic_launcher), 60, 60, 80); roundRadiusButton.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { Toast.makeText(MainActivity.this, "testest", Toast.LENGTH_LONG).show(); } }); roundRadiusButton.setClickable(false); llContainer.addView(roundRadiusButton); }}
activity_main.xml
<?xml version="1.0" encoding="utf-8"?><LinearLayout xmlns:android="http://schemas.android.com/apk/res/android" xmlns:app="http://schemas.android.com/apk/res-auto" xmlns:tools="http://schemas.android.com/tools" android:id="@+id/ll_container" android:layout_width="match_parent" android:layout_height="match_parent" android:background="#868684" android:gravity="center" android:orientation="vertical" tools:context=".MainActivity" > <com.example.newbuttiontest.RoundRadiusButton android:layout_width="300dp" android:layout_height="200dp" app:bgColor="#FFEB3B" app:drawableHeight="18dp" app:drawableWidth="18dp" app:leftDrawable="@mipmap/ic_launcher" app:leftDrawablePaddingRight="5dp" app:roundRadius="30dp" app:textColor="#FF4329" app:textSize="16dip" app:textString="testtesttest" /></LinearLayout>
attrs.xml
<?xml version="1.0" encoding="utf-8"?><resources> <declare-styleable name="RoundRadiusButton"> <attr name="roundRadius" format="dimension" /> <attr name="bgColor" format="color" /> <attr name="leftDrawable" format="reference" /> <attr name="leftDrawablePaddingRight" format="dimension" /> <attr name="drawableWidth" format="dimension" /> <attr name="drawableHeight" format="dimension" /> <attr name="textString" format="string" /> <attr name="textSize" format="dimension" /> <attr name="textColor" format="color" /> </declare-styleable></resources>
colors.xml
<resources> <color name="black_tran_30">#30000000</color></resources>
总结
以上所述是小编给大家介绍的android 自定义圆角button效果的实例代码，希望对大家有所帮助，如果大家有任何疑问请给我留言，小编会及时回复大家的。在此也非常感谢大家对我们网站的支持！如果你觉得本文对你有帮助，欢迎转载，烦请注明出处，谢谢！
本文标题: android 自定义圆角button效果的实例代码（自定义view Demo）
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