android游戏开发框架libgdx的使用(五)--舞台和常用UI类

长平狐 发布于 2013/11/25 11:38
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本文使用的libgdx是0.92版本,和现在的最新版可能有一些不一样的地方。全文内容仅供参考。

常用的UI类包括标签,按钮,勾选框,下拉框,图片,输入框,列表,滑动面板,滑条,分割面板。它们都在com.badlogic.gdx.scenes.scene2d.ui包中,都属于Actor,可以方便的纳入舞台的管理中。

其实仔细看看UI类的实现代码不难发现其实它们都是大部分继承自Widget或者Table,如果需要自定义UI可以继承以上两个类(它们继承自Actor),这里要说明一下libgdx的布局部分使用了TWL,有兴趣的朋友可以去看看。

在介绍每个控件之前我们先来看一下NinePatch,这是最近的一个比较重大的更新。

何为NinePatch?其实android原生即有NinePatch类,常在按钮中使用。

NinePatch

如图,将图片分成九份。中间部分可以根据需要扩大,使按钮的大小内容变动不受图片的限制。

而在libgdx的NinePatch其实就是九个TextureRegion对象。

常用的实例化方法有两个:

< class="brush:java;gutter:false;">public NinePatch (Texture texture, int left, int right, int top, int bottom)public NinePatch (TextureRegion region, int left, int right, int top, int bottom)

关于其中的四个int型参数如何取值我们可以参考一下源码:

< class="brush:java;gutter:false;">public NinePatch (TextureRegion region, int left, int right, int top, int bottom) { int middleWidth = region.getRegionWidth() - left - right; int middleHeight = region.getRegionHeight() - top - bottom; this.patches = new TextureRegion[] {new TextureRegion(region, 0, 0, left, top), new TextureRegion(region, left, 0, middleWidth, top), new TextureRegion(region, left + middleWidth, 0, right, top), new TextureRegion(region, 0, top, left, middleHeight), new TextureRegion(region, left, top, middleWidth, middleHeight), new TextureRegion(region, left + middleWidth, top, right, middleHeight), new TextureRegion(region, 0, top + middleHeight, left, bottom), new TextureRegion(region, left, top + middleHeight, middleWidth, bottom), new TextureRegion(region, left + middleWidth, top + middleHeight, right, bottom)}; }

先计算中间部分的宽度和高度。然后开始切图,首先取顶部的最左边的那个,即图中编号1的那块,然后去它右边的,然后再右边的。

取完最上边的那行,然后取中间的那行,然后取最后一行的。

由上自下,由左自右。

而在绘制时又是如何处理的呢?看源码:

< class="brush:java;gutter:false;">public void draw (SpriteBatch batch, float x, float y, float width, float height) { float centerColumnX = x; if (patches[BOTTOM_LEFT] != null) centerColumnX += patches[BOTTOM_LEFT].getRegionWidth(); else if (patches[MIDDLE_LEFT] != null) centerColumnX += patches[MIDDLE_LEFT].getRegionWidth(); else if (patches[TOP_LEFT] != null) // centerColumnX += patches[TOP_LEFT].getRegionWidth(); float rightColumnX = x + width; if (patches[BOTTOM_RIGHT] != null) rightColumnX -= patches[BOTTOM_RIGHT].getRegionWidth(); else if (patches[MIDDLE_RIGHT] != null) rightColumnX += patches[MIDDLE_RIGHT].getRegionWidth(); else if (patches[TOP_RIGHT] != null) // rightColumnX += patches[TOP_RIGHT].getRegionWidth(); float middleRowY = y; if (patches[TOP_LEFT] != null) middleRowY += patches[TOP_LEFT].getRegionHeight(); else if (patches[TOP_CENTER] != null) middleRowY += patches[TOP_CENTER].getRegionHeight(); else if (patches[TOP_RIGHT] != null) // middleRowY += patches[TOP_RIGHT].getRegionHeight(); float topRowY = y + height; if (patches[TOP_LEFT] != null) topRowY -= patches[TOP_LEFT].getRegionHeight(); else if (patches[TOP_CENTER] != null) topRowY -= patches[TOP_CENTER].getRegionHeight(); else if (patches[TOP_RIGHT] != null) // topRowY -= patches[TOP_RIGHT].getRegionHeight(); // Bottom row if (patches[BOTTOM_LEFT] != null) batch.draw(patches[BOTTOM_LEFT], x, y, centerColumnX - x, middleRowY - y); if (patches[BOTTOM_CENTER] != null) batch.draw(patches[BOTTOM_CENTER], centerColumnX, y, rightColumnX - centerColumnX, middleRowY - y); if (patches[BOTTOM_RIGHT] != null) batch.draw(patches[BOTTOM_RIGHT], rightColumnX, y, x + width - rightColumnX, middleRowY - y); // Middle row if (patches[MIDDLE_LEFT] != null) batch.draw(patches[MIDDLE_LEFT], x, middleRowY, centerColumnX - x, topRowY - middleRowY); if (patches[MIDDLE_CENTER] != null) batch.draw(patches[MIDDLE_CENTER], centerColumnX, middleRowY, rightColumnX - centerColumnX, topRowY - middleRowY); if (patches[MIDDLE_RIGHT] != null) batch.draw(patches[MIDDLE_RIGHT], rightColumnX, middleRowY, x + width - rightColumnX, topRowY - middleRowY); // Top row if (patches[TOP_LEFT] != null) batch.draw(patches[TOP_LEFT], x, topRowY, centerColumnX - x, y + height - topRowY); if (patches[TOP_CENTER] != null) batch.draw(patches[TOP_CENTER], centerColumnX, topRowY, rightColumnX - centerColumnX, y + height - topRowY); if (patches[TOP_RIGHT] != null) batch.draw(patches[TOP_RIGHT], rightColumnX, topRowY, x + width - rightColumnX, y + height - topRowY); }

先计算左右栏的宽度,在计算中间和顶部的高度。然后从下自上的绘制。说实话我觉得这段代码看着很好玩的。

现在来说说几个常用的控件的使用吧。先构建一个舞台。

先来试试Label吧,label是有缓存的,所以替换显示内容不是用setText方法,而是使用setWrappedText方法。

代码如下:

< class="brush:java;gutter:false;">package com.cnblogs.htynkn.listener;import com.badlogic.gdx.ApplicationListener; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.graphics.GL10; import com.badlogic.gdx.graphics.g2d.BitmapFont; import com.badlogic.gdx.graphics.g2d.BitmapFont.HAlignment; import com.badlogic.gdx.scenes.scene2d.Stage; import com.badlogic.gdx.scenes.scene2d.actors.Label;public class FirstGame implements ApplicationListener { private Stage stage; Label label; @Override public void create() { stage = new Stage(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), true); label = new Label("fpsLabel", new BitmapFont(Gdx.files.internal("cf.fnt"),Gdx.files.internal("cf.png"),false), "label1"); label.x=5; label.y=Gdx.graphics.getHeight()-label.height-5; stage.addActor(label); Gdx.input.setInputProcessor(stage); } @Override public void dispose() { stage.dispose(); } @Override public void pause() { // TODO Auto-generated method stub } @Override public void render() { Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); label.setWrappedText("FPS: "+Gdx.graphics.getFramesPerSecond(), HAlignment.CENTER); stage.act(Gdx.graphics.getDeltaTime()); stage.draw(); } @Override public void resize(int width, int height) { // TODO Auto-generated method stub } @Override public void resume() { // TODO Auto-generated method stub } }

效果:

FPS

然后再看看Button吧,实例化需要一个ButtonStyle,定义了按钮三种状态对应的图片样式,按下和松开时的X,Y偏移还有Button中文字绘制所需的BitmapFont和Color。

按钮的三种状态的图片我就省了,只用一张图片。

06

修改代码如下:

< class="brush:java;gutter:false;">package com.cnblogs.htynkn.listener;import com.badlogic.gdx.ApplicationListener; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.graphics.Color; import com.badlogic.gdx.graphics.GL10; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.BitmapFont; import com.badlogic.gdx.graphics.g2d.NinePatch; import com.badlogic.gdx.graphics.g2d.BitmapFont.HAlignment; import com.badlogic.gdx.scenes.scene2d.Stage; import com.badlogic.gdx.scenes.scene2d.actors.Label; import com.badlogic.gdx.scenes.scene2d.ui.Button; import com.badlogic.gdx.scenes.scene2d.ui.Button.ButtonStyle;public class FirstGame implements ApplicationListener { private Stage stage; Label label; Texture texture; Button button; @Override public void create() { stage = new Stage(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), true); texture = new Texture(Gdx.files.internal("06.png")); NinePatch n1 = new NinePatch(texture, 7, 7, 9, 9); BitmapFont bitmapFont = new BitmapFont(Gdx.files.internal("cf.fnt"), Gdx.files.internal("cf.png"), false); label = new Label("fpsLabel", bitmapFont, "label1"); label.x = 5; label.y = Gdx.graphics.getHeight() - label.height - 5; stage.addActor(label); button = new Button("button", new ButtonStyle(n1, n1, n1, 0f, 0f, 0f, 0f, bitmapFont, new Color(1, 1, 0, 0.5f)), "button"); button.x=10; button.y=10; button.width=100f; button.height=32f; stage.addActor(button); Gdx.input.setInputProcessor(stage); } @Override public void dispose() { stage.dispose(); } @Override public void pause() { // TODO Auto-generated method stub } @Override public void render() { Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); label.setWrappedText("FPS: " + Gdx.graphics.getFramesPerSecond(), HAlignment.CENTER); stage.act(Gdx.graphics.getDeltaTime()); stage.draw(); } @Override public void resize(int width, int height) { // TODO Auto-generated method stub } @Override public void resume() { // TODO Auto-generated method stub } }

效果:

libgdx按钮

按钮自然应该有点击事件,通过setClickListener来设置

< class="brush:java;gutter:false;">button.setClickListener(new ClickListener() { @Override public void click(Actor actor) { Gdx.app.log("Info", "点击事件触发了"); } });

然后再看看CheckBox。CheckBox的样式定义在CheckBoxStyle中,需要4个参数,两种状态的各一张图片,一个BitmapFont和Color。

这里我再添加一张图片

07

原理差不多,直接贴代码了。

< class="brush:java;gutter:false;">package com.cnblogs.htynkn.listener;import android.graphics.Paint.Align;import com.badlogic.gdx.ApplicationListener; import com.badlogic.gdx.Gdx; import com.badlogic.gdx.graphics.Color; import com.badlogic.gdx.graphics.GL10; import com.badlogic.gdx.graphics.Texture; import com.badlogic.gdx.graphics.g2d.BitmapFont; import com.badlogic.gdx.graphics.g2d.NinePatch; import com.badlogic.gdx.graphics.g2d.TextureRegion; import com.badlogic.gdx.graphics.g2d.BitmapFont.HAlignment; import com.badlogic.gdx.scenes.scene2d.Actor; import com.badlogic.gdx.scenes.scene2d.Stage; import com.badlogic.gdx.scenes.scene2d.actors.Label; import com.badlogic.gdx.scenes.scene2d.ui.Button; import com.badlogic.gdx.scenes.scene2d.ui.CheckBox; import com.badlogic.gdx.scenes.scene2d.ui.ClickListener; import com.badlogic.gdx.scenes.scene2d.ui.Button.ButtonStyle; import com.badlogic.gdx.scenes.scene2d.ui.CheckBox.CheckBoxStyle;public class FirstGame implements ApplicationListener { private Stage stage; Label label; Texture texture1; Texture texture2; CheckBox checkBox; @Override public void create() { stage = new Stage(Gdx.graphics.getWidth(), Gdx.graphics.getHeight(), true); texture1 = new Texture(Gdx.files.internal("06.png")); texture2 = new Texture(Gdx.files.internal("07.png")); NinePatch n1 = new NinePatch(texture1, 7, 7, 9, 9); BitmapFont bitmapFont = new BitmapFont(Gdx.files.internal("cf.fnt"), Gdx.files.internal("cf.png"), false); label = new Label("fpsLabel", bitmapFont, "label1"); label.x = 5; label.y = Gdx.graphics.getHeight() - label.height - 5; CheckBoxStyle style = new CheckBoxStyle(new TextureRegion(texture1), new TextureRegion(texture2), bitmapFont, new Color(1, 1, 1, 0.5f)); checkBox = new CheckBox("checkbox", style, "checkbox"); checkBox.x = 100; checkBox.y = 100; checkBox.width = 158f; checkBox.height = 32f; checkBox.setText("Yes"); checkBox.setClickListener(new ClickListener() { @Override public void click(Actor actor) { if (checkBox.isChecked) { checkBox.setText("Yes"); } else { checkBox.setText("NO"); } } }); stage.addActor(checkBox); stage.addActor(label); Gdx.input.setInputProcessor(stage); } @Override public void dispose() { stage.dispose(); } @Override public void pause() { // TODO Auto-generated method stub } @Override public void render() { Gdx.gl.glClear(GL10.GL_COLOR_BUFFER_BIT); label.setWrappedText("FPS: " + Gdx.graphics.getFramesPerSecond(), HAlignment.CENTER); stage.act(Gdx.graphics.getDeltaTime()); stage.draw(); } @Override public void resize(int width, int height) { // TODO Auto-generated method stub } @Override public void resume() { // TODO Auto-generated method stub } }

效果:

noyes

其他的UI大致用法差不多,显示的样式在对应的Style或者Skin中定义。但是要注意有些UI类需要手动设置width和height,不然有些显示会很奇怪的。

最后说一下Slider的用法。

SliderStyle需要一个NinePath和Texture,我最初没有想通为什么不是两个NinePath,仔细看一下源码才了解到,NinePath是作为背景,而Texture那个是中间的那个滑动的方块。

关于用配置文件设置Style的问题,google code的wiki上似乎没有写,但是在libgdx的论坛里面有,比如

somePatch1: [
{ height: 13, width: 9, x: 761, y: 78 },
{ height: 13, width: 1, x: 770, y: 78 },
{ height: 13, width: 9, x: 771, y: 78 },
{ height: 1, width: 9, x: 761, y: 91 },
{ height: 1, width: 1, x: 770, y: 91 },
{ height: 1, width: 9, x: 771, y: 91 },
{ height: 13, width: 9, x: 761, y: 92 },
{ height: 13, width: 1, x: 770, y: 92 },
{ height: 13, width: 9, x: 771, y: 92 }
]
或者
somePatch2: [
{ height: 13, width: 9, x: 761, y: 78 },
]

原文链接:http://www.cnblogs.com/htynkn/archive/2011/11/16/libgdx_5.html
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