Android 它们的定义View视图
2015-08-16 19:02
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创建一个新视图将满足我们独特UI需求。
本文介绍的发展将指南针罗盘接口使用UI,通过继承View定义自己的视图类工具,为了深入了解自己的自定义视图。
实现效果图:
源码:
布局文件activity_main(当中CompassView继承View类):
res/values目录下的:
string.xml:
colors.xml:
MainActivity:
CompassView:
源码下载:
点击下载源代码
本文介绍的发展将指南针罗盘接口使用UI,通过继承View定义自己的视图类工具,为了深入了解自己的自定义视图。
实现效果图:
源码:
布局文件activity_main(当中CompassView继承View类):
<FrameLayout 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=".MainActivity" > <com.professionalandroiddemo6.CompassView android:id="@+id/compassView" android:layout_width="match_parent" android:layout_height="match_parent" /> </FrameLayout>
res/values目录下的:
string.xml:
<?xml version="1.0" encoding="utf-8"? > <resources> <string name="app_name">ProfessionalAndroidDemo6</string> <string name="action_settings" font = "14sp">Settings</string> <string name="hello_world">Hello world!</string> <string name="north">N</string> <string name="east">E</string> <string name="south">S</string> <string name="west">W</string> </resources>
colors.xml:
<?xml version="1.0" encoding="utf-8"?> <resources> <color name="background">#F555</color> <color name="maker">#AFFF</color> <color name="text">#AFFF</color> </resources>代码文件;
MainActivity:
package com.professionalandroiddemo6; import android.app.Activity; import android.os.Bundle; public class MainActivity extends Activity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } }
CompassView:
package com.professionalandroiddemo6; /** * 自己定义视图--指南针界面 */ import android.content.Context; import android.content.res.Resources; import android.graphics.Canvas; import android.graphics.Paint; import android.util.AttributeSet; import android.view.View; import android.view.accessibility.AccessibilityEvent; public class CompassView extends View { private Paint markerPaint; private Paint circlePaint; private Paint textPaint; private String north, south, east, west; private int textHeight; private String dirString; private float bearing; public void setBearing(float _bearing) { bearing = _bearing; sendAccessibilityEvent(AccessibilityEvent.TYPE_VIEW_TEXT_CHANGED); } public float getBearing() { return bearing; } public CompassView(Context context) { super(context); initCompassView(); } public CompassView(Context context, AttributeSet attrs) { super(context, attrs); initCompassView(); } public CompassView(Context context, AttributeSet attrs, int defStyleAttr) { super(context, attrs, defStyleAttr); initCompassView(); } private void initCompassView() { setFocusable(true); Resources resources = this.getResources(); circlePaint = new Paint(Paint.ANTI_ALIAS_FLAG); circlePaint.setColor(resources.getColor(R.color.background)); circlePaint.setStrokeWidth(1); circlePaint.setStyle(Paint.Style.FILL_AND_STROKE); north = resources.getString(R.string.north); south = resources.getString(R.string.south); east = resources.getString(R.string.east); west = resources.getString(R.string.west); textPaint = new Paint(Paint.ANTI_ALIAS_FLAG); textPaint.setColor(resources.getColor(R.color.text)); textPaint.setTextSize((float) 30);// 此处设置将要显示的字体的大小。 textHeight = (int) textPaint.measureText("yY"); markerPaint = new Paint(Paint.ANTI_ALIAS_FLAG); markerPaint.setColor(resources.getColor(R.color.maker)); } @Override protected void onMeasure(int widthMeasureSpec, int heightMeasureSpec) { // 罗盘是一个填充尽可能多的空间的圆。通过设置最短的边界、高度或者宽度来设置測量的尺寸。 int measuredWidth = measure(widthMeasureSpec); int measuredHeight = measure(heightMeasureSpec); int d = Math.min(measuredWidth, measuredHeight); setMeasuredDimension(d, d); } private int measure(int measureSpec) { int result = 0; // 对測量说明进行解码 int specMode = MeasureSpec.getMode(measureSpec); int specSize = MeasureSpec.getSize(measureSpec); if (specMode == MeasureSpec.UNSPECIFIED) { // 假设没有指定界限了,则默认返回值为200 result = 200; } else { // 因为你希望填充可用的空间,所以总是返回整个可用的边界 result = specSize; } return result; } @Override protected void onDraw(Canvas canvas) { // 找到控件的中心。并将最小边的长度作为罗盘的半径存储起来。 int mMeasuredWidth = getMeasuredWidth(); int mMeasuredHeight = getMeasuredHeight(); int px = mMeasuredWidth / 2; int py = mMeasuredHeight / 2; int radius = Math.min(px, py); // 使用drawCircle方法画出罗盘字符的边界,并为其北京着色。 canvas.drawCircle(px, py, radius, circlePaint); canvas.save(); canvas.rotate(-bearing, px, py); // 剩下要做的就仅仅有绘制标记了。把画布旋转一圈,而且每15度画一个标记,每45度画一个方向的缩写。 int textWidth = (int) textPaint.measureText("W"); int cardinalX = px - textWidth / 2; int cardinalY = py - radius + textHeight; // 每15度绘制一个标记,每45度绘制一个文本 for (int i = 0; i < 24; i++) { canvas.drawLine(px, py - radius, px, py - radius + 20, markerPaint); canvas.save(); canvas.translate(0, textHeight); // 绘制基本方位 if (i % 6 == 0) { switch (i) { case 0: { dirString = north; int arrowY = 2 * textHeight; canvas.drawLine(px, arrowY, px - 5, 5 * textHeight, markerPaint); canvas.drawLine(px, arrowY, px + 5, 5 * textHeight, markerPaint); } break; case 6: dirString = east; break; case 12: dirString = south; break; case 18: dirString = west; break; } canvas.drawText(dirString, cardinalX, cardinalY, textPaint); } else if (i % 3 == 0) { // 每45度绘制文本 String angle = String.valueOf(i * 15); float angleTextWidth = textPaint.measureText(angle); int angleTextX = (int) (px - angleTextWidth / 2); int angleTextY = py - radius + textHeight; canvas.drawText(angle, angleTextX, angleTextY, textPaint); } canvas.restore(); canvas.rotate(15, px, py); } canvas.restore(); } @Override public boolean dispatchPopulateAccessibilityEvent(AccessibilityEvent event) { super.dispatchPopulateAccessibilityEvent(event); if (isShown()) { String bearingStr = String.valueOf(bearing); if (bearingStr.length() > AccessibilityEvent.MAX_TEXT_LENGTH) bearingStr = bearingStr.substring(0, AccessibilityEvent.MAX_TEXT_LENGTH); event.getText().add(bearingStr); return true; } return false; } }
源码下载:
点击下载源代码
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