自定义View（一）——画线、矩形、圆形、图像

一、最简单的自定义View，什么都不显示，但是有View的特性

com.cctvjiatao.customview.MainActivity

package com.cctvjiatao.customview;import android.app.Activity;import android.os.Bundle;public class MainActivity extends Activity {@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_main);}}

com.cctvjiatao.customview.v1.CustomView1

package com.cctvjiatao.customview.v1;import android.content.Context;import android.util.AttributeSet;import android.view.View;/** * @作者： jiatao * @修改时间：2016-3-11 上午7:58:10 * @包名：com.cctvjiatao.customview.v1 * @文件名：CustomView1.java * @版权声明：www.cctvjiatao.com * @功能： 最简单的自定义View，什么都不显示，但是有View的特性 */public class CustomView1 extends View {public CustomView1(Context context) {super(context);}public CustomView1(Context context, AttributeSet attrs) {super(context, attrs);}}

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/container"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <com.cctvjiatao.customview.v1.CustomView1        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="#00ff00" >    </com.cctvjiatao.customview.v1.CustomView1></FrameLayout>

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?><manifest xmlns:android="http://schemas.android.com/apk/res/android"    package="com.cctvjiatao.customview"    android:versionCode="1"    android:versionName="1.0" >    <uses-sdk        android:minSdkVersion="14"        android:targetSdkVersion="21" />    <application        android:allowBackup="true"        android:icon="@drawable/ic_launcher"        android:label="@string/app_name"        android:theme="@style/AppTheme" >        <activity            android:name=".MainActivity"            android:label="@string/app_name" >            <intent-filter>                <action android:name="android.intent.action.MAIN" />                <category android:name="android.intent.category.LAUNCHER" />            </intent-filter>        </activity>    </application></manifest>

效果图：

二、自定义View，显示一行文字。注意:drawText的坐标是 “左下” 坐标。
com.cctvjiatao.customview.MainActivity 同一

AndroidManifest.xml 同一

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/container"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <com.cctvjiatao.customview.v1.CustomView1        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="#00ff00"         android:visibility="gone">    </com.cctvjiatao.customview.v1.CustomView1>        <com.cctvjiatao.customview.v2.CustomView1        android:layout_width="match_parent"        android:layout_height="match_parent">    </com.cctvjiatao.customview.v2.CustomView1></FrameLayout>

com.cctvjiatao.customview.v2.CustomView1

package com.cctvjiatao.customview.v2;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.util.AttributeSet;import android.view.View;/** * @作者： jiatao * @修改时间：2016-3-11 上午8:22:56 * @包名：com.cctvjiatao.customview.v2 * @文件名：CustomView2.java * @版权声明：www.cctvjiatao.com * @功能： 自定义View，显示一行文字。注意:drawText的坐标是 “左下” 坐标。 */public class CustomView1 extends View {public CustomView1(Context context, AttributeSet attrs) {super(context, attrs);}public CustomView1(Context context) {super(context);}@Overrideprotected void onDraw(Canvas canvas) {Paint paint = new Paint();// canvas.drawText("This is a canvas", 0, 0, paint);//这样写不会显示文字，因为文字的左下坐标是（0，0）canvas.drawText("This is a canvas,坐标为左下（0，50）", 0, 50, paint);// (字符，左坐标，下坐标，画笔)paint.setTextSize(30);//设置画笔大小，即字体大小canvas.drawText("This is a canvas，坐标为左下（0，30）", 0, 30, paint);// (字符，左坐标，下坐标，画笔)}}

效果图：

三、 自定义View，画线、矩形、圆角矩形、圆形

com.cctvjiatao.customview.MainActivity 同一

AndroidManifest.xml 同一

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/container"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <com.cctvjiatao.customview.v1.CustomView1        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="#00ff00"         android:visibility="gone">    </com.cctvjiatao.customview.v1.CustomView1>        <com.cctvjiatao.customview.v2.CustomView1        android:layout_width="match_parent"        android:layout_height="match_parent"        android:visibility="gone">    </com.cctvjiatao.customview.v2.CustomView1>        <com.cctvjiatao.customview.v2.CustomView2        android:layout_width="match_parent"        android:layout_height="match_parent">    </com.cctvjiatao.customview.v2.CustomView2></FrameLayout>

com.cctvjiatao.customview.v2.CustomView2

<pre name="code" class="java">package com.cctvjiatao.customview.v2;import android.content.Context;import android.graphics.Canvas;import android.graphics.Paint;import android.graphics.Rect;import android.graphics.RectF;import android.graphics.Paint.Style;import android.util.AttributeSet;import android.view.View;/** * @作者： jiatao * @修改时间：2016-3-12 上午11:31:51 * @包名：com.cctvjiatao.customview.v2 * @文件名：CustomView2.java * @版权声明：www.cctvjiatao.com * @功能： 自定义View，画线、矩形、圆角矩形、圆形 */public class CustomView2 extends View {public CustomView2(Context context, AttributeSet attrs) {super(context, attrs);}public CustomView2(Context context) {super(context);}@Overrideprotected void onDraw(Canvas canvas) {Paint paint = new Paint();paint.setTextSize(10);paint.setColor(0xffff0000);// 画直线canvas.drawLine(0, 10, 200, 10, paint);// 画斜线canvas.drawLine(0, 10, 200, 60, paint);// 画矩形(Rect)Rect rect = new Rect(0, 80, 100, 160);canvas.drawRect(rect, paint);// 画矩形(RectF)RectF rectf = new RectF(150, 80, 250, 160);canvas.drawRect(rectf, paint);// 画矩形(坐标)canvas.drawRect(300, 80, 400, 160, paint);// 画圆角矩形(RectF)RectF rectrf = new RectF(10, 180, 110, 250);canvas.drawRoundRect(rectrf, 10, 10, paint);// 画圆角矩形(RectF)canvas.drawRoundRect(120, 180, 220, 250, 10, 10, paint);// 画圆形canvas.drawCircle(100, 350, 50, paint);paint.setStyle(Style.STROKE);canvas.drawCircle(210, 350, 50, paint);paint.setStyle(Style.FILL_AND_STROKE);canvas.drawCircle(320, 350, 50, paint);paint.setStyle(Style.FILL);canvas.drawCircle(430, 350, 50, paint);}}

效果图：

四、自定义View，画图像

com.cctvjiatao.customview.MainActivity 同一

AndroidManifest.xml 同一

activity_main.xml

<FrameLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:id="@+id/container"    android:layout_width="match_parent"    android:layout_height="match_parent" >    <com.cctvjiatao.customview.v1.CustomView1        android:layout_width="match_parent"        android:layout_height="match_parent"        android:background="#00ff00"         android:visibility="gone">    </com.cctvjiatao.customview.v1.CustomView1>        <com.cctvjiatao.customview.v2.CustomView1        android:layout_width="match_parent"        android:layout_height="match_parent"        android:visibility="gone">    </com.cctvjiatao.customview.v2.CustomView1>        <com.cctvjiatao.customview.v2.CustomView2        android:layout_width="match_parent"        android:layout_height="match_parent"        android:visibility="gone">    </com.cctvjiatao.customview.v2.CustomView2>        <com.cctvjiatao.customview.v2.CustomView3        android:layout_width="match_parent"        android:layout_height="match_parent">    </com.cctvjiatao.customview.v2.CustomView3></FrameLayout>

com.cctvjiatao.customview.v2.CustomView3

package com.cctvjiatao.customview.v2;import com.cctvjiatao.customview.R;import android.content.Context;import android.graphics.Bitmap;import android.graphics.BitmapFactory;import android.graphics.Canvas;import android.graphics.Paint;import android.util.AttributeSet;import android.view.View;/** * @作者： jiatao * @修改时间：2016-3-12 下午1:16:11 * @包名：com.cctvjiatao.customview.v2 * @文件名：CustomView3.java * @版权声明：www.cctvjiatao.com * @功能： 自定义View，画图像 */public class CustomView3 extends View {private Bitmap bitmap;public CustomView3(Context context, AttributeSet attrs) {super(context, attrs);bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);}public CustomView3(Context context) {super(context);bitmap = BitmapFactory.decodeResource(getResources(), R.drawable.ic_launcher);}@Overrideprotected void onDraw(Canvas canvas) {Paint paint = new Paint();canvas.drawBitmap(bitmap, 0, 35, paint);}}

效果图：