2.3.3 Button(按钮)与ImageButton(图像按钮)

本节引言：

今天给大家介绍的Android基本控件中的两个按钮控件，Button普通按钮和ImageButton图像按钮； 其实ImageButton和Button的用法基本类似，至于与图片相关的则和后面ImageView相同，所以本节 只对Button进行讲解，另外Button是TextView的子类，所以TextView上很多属性也可以应用到Button 上！我们实际开发中对于Button的，无非是对按钮的几个状态做相应的操作，比如：按钮按下的时候 用一种颜色，弹起又一种颜色，或者按钮不可用的时候一种颜色这样！上述实现无非是通过 StateListDrawable这种Drawable资源来实现，即编写一个drawable的资源文件，就说这么多， 直接开始本节内容~

---

1.StateListDrawable简介：

StateListDrawable是Drawable资源的一种，可以根据不同的状态，设置不同的图片效果，关键节点 < selector >，我们只需要将Button的background属性设置为该drawable资源即可轻松实现，按下 按钮时不同的按钮颜色或背景！

我们可以设置的属性：

• drawable:引用的Drawable位图,我们可以把他放到最前面,就表示组件的正常状态~
• state_focused:是否获得焦点
• state_window_focused:是否获得窗口焦点
• state_enabled:控件是否可用
• state_checkable:控件可否被勾选,eg:checkbox
• state_checked:控件是否被勾选
• state_selected:控件是否被选择,针对有滚轮的情况
• state_pressed:控件是否被按下
• state_active:控件是否处于活动状态,eg:slidingTab
• state_single:控件包含多个子控件时,确定是否只显示一个子控件
• state_first:控件包含多个子控件时,确定第一个子控件是否处于显示状态
• state_middle:控件包含多个子控件时,确定中间一个子控件是否处于显示状态
• state_last:控件包含多个子控件时,确定最后一个子控件是否处于显示状态

---

2.实现按钮的按下效果：

好的，先准备三个图片背景，一般我们为了避免按钮拉伸变形都会使用.9.png作为按钮的drawable！ 先来看下 运行效果图：

代码实现：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
    <item android:state_pressed="true" android:drawable="@drawable/ic_course_bg_fen"/>
    <item android:state_enabled="false" android:drawable="@drawable/ic_course_bg_pressed"/>
    <item android:drawable="@drawable/ic_course_bg_cheng"/>
</selector>

布局文件:activity_main.xml

<Button
        android:id="@+id/btnOne"
        android:layout_width="match_parent"
        android:layout_height="64dp"
        android:background="@drawable/btn_bg1"
        android:text="按钮"/>
</span><span class="tag">&lt;Button</span><span class="pln">
    </span><span class="atn">android:id</span><span class="pun">=</span><span class="atv">"@+id/btnTwo"</span><span class="pln">
    </span><span class="atn">android:layout_width</span><span class="pun">=</span><span class="atv">"match_parent"</span><span class="pln">
    </span><span class="atn">android:layout_height</span><span class="pun">=</span><span class="atv">"64dp"</span><span class="pln">
    </span><span class="atn">android:text</span><span class="pun">=</span><span class="atv">"按钮不可用"</span><span class="tag">/&gt;</span></pre>

MainActivity.java：

public class MainActivity extends Activity {
</span><span class="kwd">private</span><span class="pln"> </span><span class="typ">Button</span><span class="pln"> btnOne</span><span class="pun">,</span><span class="pln">btnTwo</span><span class="pun">;</span><span class="pln">

</span><span class="lit">@Override</span><span class="pln">
</span><span class="kwd">protected</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> onCreate</span><span class="pun">(</span><span class="typ">Bundle</span><span class="pln"> savedInstanceState</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
    </span><span class="kwd">super</span><span class="pun">.</span><span class="pln">onCreate</span><span class="pun">(</span><span class="pln">savedInstanceState</span><span class="pun">);</span><span class="pln">
    setContentView</span><span class="pun">(</span><span class="pln">R</span><span class="pun">.</span><span class="pln">layout</span><span class="pun">.</span><span class="pln">activity_main</span><span class="pun">);</span><span class="pln">
    btnOne </span><span class="pun">=</span><span class="pln"> </span><span class="pun">(</span><span class="typ">Button</span><span class="pun">)</span><span class="pln"> findViewById</span><span class="pun">(</span><span class="pln">R</span><span class="pun">.</span><span class="pln">id</span><span class="pun">.</span><span class="pln">btnOne</span><span class="pun">);</span><span class="pln">
    btnTwo </span><span class="pun">=</span><span class="pln"> </span><span class="pun">(</span><span class="typ">Button</span><span class="pun">)</span><span class="pln"> findViewById</span><span class="pun">(</span><span class="pln">R</span><span class="pun">.</span><span class="pln">id</span><span class="pun">.</span><span class="pln">btnTwo</span><span class="pun">);</span><span class="pln">
    btnTwo</span><span class="pun">.</span><span class="pln">setOnClickListener</span><span class="pun">(</span><span class="kwd">new</span><span class="pln"> </span><span class="typ">OnClickListener</span><span class="pun">()</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
        </span><span class="lit">@Override</span><span class="pln">
        </span><span class="kwd">public</span><span class="pln"> </span><span class="kwd">void</span><span class="pln"> onClick</span><span class="pun">(</span><span class="typ">View</span><span class="pln"> v</span><span class="pun">)</span><span class="pln"> </span><span class="pun">{</span><span class="pln">
            </span><span class="kwd">if</span><span class="pun">(</span><span class="pln">btnTwo</span><span class="pun">.</span><span class="pln">getText</span><span class="pun">().</span><span class="pln">toString</span><span class="pun">().</span><span class="pln">equals</span><span class="pun">(</span><span class="str">"按钮不可用"</span><span class="pun">)){</span><span class="pln">
                btnOne</span><span class="pun">.</span><span class="pln">setEnabled</span><span class="pun">(</span><span class="kwd">false</span><span class="pun">);</span><span class="pln">
                btnTwo</span><span class="pun">.</span><span class="pln">setText</span><span class="pun">(</span><span class="str">"按钮可用"</span><span class="pun">);</span><span class="pln">
            </span><span class="pun">}</span><span class="kwd">else</span><span class="pun">{</span><span class="pln">
                btnOne</span><span class="pun">.</span><span class="pln">setEnabled</span><span class="pun">(</span><span class="kwd">true</span><span class="pun">);</span><span class="pln">
                btnTwo</span><span class="pun">.</span><span class="pln">setText</span><span class="pun">(</span><span class="str">"按钮不可用"</span><span class="pun">);</span><span class="pln">
            </span><span class="pun">}</span><span class="pln">
        </span><span class="pun">}</span><span class="pln">
    </span><span class="pun">});</span><span class="pln">
</span><span class="pun">}</span><span class="pln">

}

---

3.使用颜色值绘制圆角按钮

很多时候我们不一定会有美工是吧，或者我们不会PS或毁图秀秀，又或者我们懒，不想自己去做图， 这个时候我们可以自己写代码来作为按钮背景，想要什么颜色就什么颜色，下面我们来定制个圆角的 的按钮背景~，这里涉及到另一个drawable资源:ShapeDrawable，这里不详细讲，后面会详细介绍每一个 drawable~这里会用就好，只是EditText修改下Background属性而已，这里只贴drawable资源！

先看下效果图：

bbuton_danger_rounded.xml：

<?xml version="1.0" encoding="utf-8"?>
<selector xmlns:android="http://schemas.android.com/apk/res/android">
</span><span class="tag">&lt;item</span><span class="pln"> </span><span class="atn">android:state_pressed</span><span class="pun">=</span><span class="atv">"true"</span><span class="tag">&gt;&lt;shape&gt;</span><span class="pln">
        </span><span class="tag">&lt;solid</span><span class="pln"> </span><span class="atn">android:color</span><span class="pun">=</span><span class="atv">"@color/bbutton_danger_pressed"</span><span class="pln"> </span><span class="tag">/&gt;</span><span class="pln">
        </span><span class="tag">&lt;stroke</span><span class="pln"> </span><span class="atn">android:width</span><span class="pun">=</span><span class="atv">"1dp"</span><span class="pln"> </span><span class="atn">android:color</span><span class="pun">=</span><span class="atv">"@color/bbutton_danger_edge"</span><span class="pln"> </span><span class="tag">/&gt;</span><span class="pln">
        </span><span class="tag">&lt;corners</span><span class="pln"> </span><span class="atn">android:radius</span><span class="pun">=</span><span class="atv">"@dimen/bbuton_rounded_corner_radius"</span><span class="tag">/&gt;</span><span class="pln">
    </span><span class="tag">&lt;/shape&gt;&lt;/item&gt;</span><span class="pln">
    

</span><span class="tag">&lt;item</span><span class="pln"> </span><span class="atn">android:state_enabled</span><span class="pun">=</span><span class="atv">"false"</span><span class="tag">&gt;&lt;shape&gt;</span><span class="pln">
    </span><span class="tag">&lt;solid</span><span class="pln"> </span><span class="atn">android:color</span><span class="pun">=</span><span class="atv">"@color/bbutton_danger_disabled"</span><span class="pln"> </span><span class="tag">/&gt;</span><span class="pln">
        </span><span class="tag">&lt;stroke</span><span class="pln"> </span><span class="atn">android:width</span><span class="pun">=</span><span class="atv">"1dp"</span><span class="pln"> </span><span class="atn">android:color</span><span class="pun">=</span><span class="atv">"@color/bbutton_danger_disabled_edge"</span><span class="pln"> </span><span class="tag">/&gt;</span><span class="pln">
        </span><span class="tag">&lt;corners</span><span class="pln"> </span><span class="atn">android:radius</span><span class="pun">=</span><span class="atv">"@dimen/bbuton_rounded_corner_radius"</span><span class="tag">/&gt;</span><span class="pln">
    </span><span class="tag">&lt;/shape&gt;&lt;/item&gt;</span><span class="pln">
    

</span><span class="tag">&lt;item&gt;&lt;shape&gt;</span><span class="pln">
        </span><span class="tag">&lt;solid</span><span class="pln"> </span><span class="atn">android:color</span><span class="pun">=</span><span class="atv">"@color/bbutton_danger"</span><span class="pln"> </span><span class="tag">/&gt;</span><span class="pln">
        </span><span class="tag">&lt;stroke</span><span class="pln"> </span><span class="atn">android:width</span><span class="pun">=</span><span class="atv">"1dp"</span><span class="pln"> </span><span class="atn">android:color</span><span class="pun">=</span><span class="atv">"@color/bbutton_danger_edge"</span><span class="pln"> </span><span class="tag">/&gt;</span><span class="pln">
        </span><span class="tag">&lt;corners</span><span class="pln"> </span><span class="atn">android:radius</span><span class="pun">=</span><span class="atv">"@dimen/bbuton_rounded_corner_radius"</span><span class="tag">/&gt;</span><span class="pln">
    </span><span class="tag">&lt;/shape&gt;&lt;/item&gt;</span><span class="pln">

</selector>

color.xml:

<?xml version="1.0" encoding="utf-8"?>
<resources>
    <color name="bbutton_danger_pressed">#ffd2322d</color>
    <color name="bbutton_danger_edge">#ffd43f3a</color>
    <color name="bbutton_danger_disabled">#a5d9534f</color>
    <color name="bbutton_danger_disabled_edge">#a5d43f3a</color>
    <color name="bbutton_danger">#ffd9534f</color>
    <color name="text_font_white">#FFFFFF</color>
</resources>

---

dimens.xml:

<dimen name="bbuton_rounded_corner_radius">5dp</dimen>

---

4.实现Material Design水波效果的Button

如果你的Android手机是5.0以上的系统，相信对下面这种按钮点击效果并不会陌生：

实现效果图：

快的那个是按下后的效果，慢的是长按后的效果！

实现逻辑：

1.我们继承ImageButton，当然你可以换成Button或者View,这里笔者想把龟放到中间才继承ImageButton

2.首先，创建两个Paint(画笔)对象，一个绘制底部背景颜色，一个绘制波纹扩散的

3.接着计算最大半径，开始半径每隔一段时间递增一次，直到等于最大半径，然后重置状态！

PS:大概的核心，刚学可能对自定义View感到陌生，没事，这里了解下即可，以后我们会讲，当然 你可以自己扣扣，注释还是蛮详细的~

实现代码：

自定义ImageButton：MyButton.java

package demo.com.jay.buttondemo;

import android.content.Context;
import android.graphics.Canvas;
import android.graphics.Paint;
import android.os.SystemClock;
import android.util.AttributeSet;
import android.view.MotionEvent;
import android.view.ViewConfiguration;
import android.widget.ImageButton;

/**

• Created by coder-pig on 2015/7/16 0016.
  */
  public class MyButton extends ImageButton {

  private static final int INVALIDATE_DURATION = 15; //每次刷新的时间间隔
  private static int DIFFUSE_GAP = 10; //扩散半径增量
  private static int TAP_TIMEOUT; //判断点击和长按的时间

  private int viewWidth, viewHeight; //控件宽高
  private int pointX, pointY; //控件原点坐标（左上角）
  private int maxRadio; //扩散的最大半径
  private int shaderRadio; //扩散的半径

  private Paint bottomPaint, colorPaint;