自定义view对我来说一直是比较恐惧的,但是万事开头难,今天总结一下自己实现圆形TextView的三种方式。
首先来说一下自定义view的三种方式:
一,自绘控件:
自绘控件就是说界面展示的内容就是我们在ondraw()方法中绘制出来的,继承View.
二,组合控件:
顾名思义,由多个控件组合在一起的控件,这里面组合的控件并不需要我们自己去绘制,用Android原生的即可。最常见的就是标题栏,将图标,文字组合到一个布局中,自定义组合控件时继承Framelayout,通过 LayoutInflater.from(context).inflate(R.layout.title, this); 来引用布局即可。
三,继承控件:
顾名思义,继承android原生的已有控件,在此基础上进行绘制,那么我们就可以在原有的功能上增加新的功能。
自定义view的步骤:
1:自定义属性,在values中创建attrs文件
2:在构造方法中获取自定义属性,
public View (Context context)是在Java代码创建视图的时候被调用,如果是从xml填充的视图,就不会调用这个
public View (Context context, AttributeSet attrs)这个是在xml创建但是没有指定style的时候被调用
public View (Context context, AttributeSet attrs, int defStyle)这个是在xml创建,引用默认style的时候被调用
3:重写onMesure(),测量控件高度;
4:重写onDraw(),绘制控件;
Demo
圆形TextView的实现:
方式一(自绘控件):
1.1自定义属性
<?xml version="1.0" encoding="utf-8"?><resources> <declare-styleable name="CustomTextView"> <attr name="mTextSize" format="dimension"/> <attr name="mTextColor" format="color"/> <attr name="mBackgroudColor" format="color"/> <attr name="mRound" format="dimension"/> <attr name="mText" format="string"/> </declare-styleable></resources>
1.2获取属性
public CustomTextView(Context context, AttributeSet attrs) { super(context, attrs) TypedArray array = null try { array = context.getTheme().obtainStyledAttributes(attrs, R.styleable.CustomTextView, 0, 0) mTextSize = array.getDimension(R.styleable.CustomTextView_mTextSize, 14) mTextColor = array.getColor(R.styleable.CustomTextView_mTextColor, Color.BLACK) mBackgroudColor = array.getColor(R.styleable.CustomTextView_mBackgroudColor, Color.YELLOW) mRound = array.getColor(R.styleable.CustomTextView_mRound, 5) mText = array.getString(R.styleable.CustomTextView_mText) } finally { array.recycle() } init() }
1.3重写onMesure();
@Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int width = 48; int height = 48; if (widthMode == MeasureSpec.EXACTLY) { width = widthSize; } else { width = Math.min(width, widthSize); } if (heightMode == MeasureSpec.EXACTLY) { height = heightSize; } else { height = Math.min(height, heightSize); } setMeasuredDimension(width, height); }
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
1.4重写onDraw();
@Override protected void onDraw(Canvas canvas) { super.onDraw(canvas) paint.setColor(mBackgroudColor) canvas.drawCircle(getWidth() / 2, getHeight() / 2, getWidth() / 2, paint) paint.setColor(mTextColor) canvas.drawText(mText, getWidth() / 2 - rect.width() / 2, getHeight() / 2 + rect.height() / 2, paint) }
添加布局
<com.example.com.customview.CustomTextView android:layout_width="100dp" android:layout_height="100dp" app:mText="你好" android:layout_margin="8dp" app:mTextColor="@color/colorPrimary" app:mTextSize="16sp" app:mBackgroudColor="#F00"/>
方式二(继承控件):
package com.example.com.customview;import android.content.Context;import android.graphics.Canvas;import android.graphics.Color;import android.graphics.Paint;import android.graphics.Rect;import android.util.AttributeSet;import android.widget.TextView;/** * Created by Administrator on 2016/9/5. */public class CustomView extends TextView{ private Rect rect; private Paint paint; public CustomView(Context context) { super(context); } public CustomView(Context context, AttributeSet attrs) { super(context, attrs); rect=new Rect(); paint=new Paint(); paint.setColor(Color.RED); paint.setStyle(Paint.Style.FILL); paint.setAntiAlias(true); paint.setDither(true); } public CustomView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { int widthMode = MeasureSpec.getMode(widthMeasureSpec); int widthSize = MeasureSpec.getSize(widthMeasureSpec); int heightMode = MeasureSpec.getMode(heightMeasureSpec); int heightSize = MeasureSpec.getSize(heightMeasureSpec); int width = 48; int height = 48; if(widthMode==MeasureSpec.EXACTLY||heightMode==MeasureSpec.EXACTLY){ width=widthSize; height=heightSize; width=Math.max(width,height); } setMeasuredDimension(width,width); } @Override protected void onDraw(Canvas canvas) { canvas.drawCircle(getWidth()/2,getHeight()/2,Math.max(getWidth(), getHeight())/2,paint); super.onDraw(canvas); }}
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
- 1
- 2
- 3
- 4
- 5
- 6
- 7
- 8
- 9
- 10
- 11
- 12
- 13
- 14
- 15
- 16
- 17
- 18
- 19
- 20
- 21
- 22
- 23
- 24
- 25
- 26
- 27
- 28
- 29
- 30
- 31
- 32
- 33
- 34
- 35
- 36
- 37
- 38
- 39
- 40
- 41
- 42
- 43
- 44
- 45
- 46
- 47
- 48
- 49
- 50
- 51
- 52
- 53
- 54
- 55
- 56
- 57
- 58
- 59
在drawCircle放在 super.onDraw(canvas);前面,因为如果父类先画text的话,画圆的时候会被遮盖,所以先画圆,在调用父类的ondraw();
方式三(shape):
<?xml version="1.0" encoding="utf-8"?><shape xmlns:android="http://schemas.android.com/apk/res/android" android:shape="oval" android:useLevel="false"> <solid android:color="#F00"/> <size android:height="48dp" android:width="48dp"/></shape>
在布局中添加背景
<TextView android:layout_width="100dp" android:layout_height="100dp" android:text="shape" android:gravity="center" android:layout_margin="8dp" android:background="@drawable/bg_circle"/>
看看三种方式的实现效果:
就这些了,讲的不是很详细,因为一些概念基础我也不是很理解,只能先实现看看咯!