Listening-based Event response for Android development event response

<span id="Label3"></p>Listening-based Event response for Android development event response<p><p>This article describes how the Android operating system responds to events by Listening.</p></p><p><p></p></p> <ul> <ul> <li>Listening-based Event response for Android development event response <ul> <li> <ul> <li>Background introduction</li> <li>Android Development Event Response type</li> <li>Inner class</li> <li>Anonymous inner class</li> <li>External class</li> <li>Direct Binding Label</li> <li>Summarize</li> </ul></li> </ul></li> </ul> </ul><p><p></p></p>Background introduction<p><p>For any visual development, the response to the control will be Involved. We use the example: to implement a click on the button buttons to explain the corresponding method of the event in Android.</p></p>Android Development Event Response type<p><p>In Android development, there are two ways to respond to events, namely:<br>-listen-based Event Handling<br>-callback-based Event Handling</p></p><p><p>In this paper, we focus on the analysis based on monitoring-based event processing, There are five main ways to Implement:<br>-inner class<br>-internal Anonymous Class<br>-external class<br>-direct binding Label<br>-activity itself as an event listener tag</p></p><p><p>I personally have no sense of the fifth way, so I don't do a detailed introduction here.</p></p>Inner class<p><p>The inner class is the most common method we need to first use Setonclicklistener to bind the class that handles the response message:</p></p><pre class="prettyprint"><pre class="prettyprint"><code class=" hljs cs"><span class="hljs-comment">// 内部类</span> button2.setOnClickListener(<span class="hljs-keyword">new</span> MyOnClickListener());</code></pre></pre><p><p>Then in the activity you designed, create an inner class:</p></p><pre class="prettyprint"><pre class="prettyprint"><code class=" hljs java"><span class="hljs-keyword">public</span><span class="hljs-class"><span class="hljs-keyword">class</span> <span class="hljs-title">MyOnClickListener</span> <span class="hljs-keyword">implements</span> <span class="hljs-title">View</span>.<span class="hljs-title">OnClickListener</span>{</span> <span class="hljs-annotation">@Override</span> <span class="hljs-keyword">public</span><span class="hljs-keyword">void</span><span class="hljs-title">onClick</span>(View v){ <span class="hljs-string">"内部类"</span>, Toast.LENGTH_SHORT).show(); } }</code></pre></pre><p><p>personally, the inner class is the most suggested method, because you can design an inner class that accepts all the messages that the button responds To.</p></p>Anonymous inner class<p><p>The following is an example of an anonymous inner class:</p></p><pre class="prettyprint"><pre class="prettyprint"><code class=" hljs java"><span class="hljs-comment">// 内部匿名类</span>button1.setOnClickListener(<span class="hljs-keyword">new</span> View.OnClickListener() { <span class="hljs-annotation">@Override</span> <span class="hljs-keyword">public</span><span class="hljs-keyword">void</span><span class="hljs-title">onClick</span>(View v) { <span class="hljs-string">"内部匿名类"</span>, Toast.LENGTH_SHORT).show(); }});</code></pre></pre>External class<p><p>The external class, in Layman's terms, is to create A. Java file to write the response to a button click event, here's an example, outerclass is the class I wrote to respond to the button event:</p></p><pre class="prettyprint"><code class=" hljs java"><code class="hljs java"><span class="hljs-keyword">import </span> android.app.Activity; <span class="hljs-keyword">import </span> android.view.View; <span class="hljs-keyword">import </span> android.widget.Toast; <span class="hljs-javadoc">/** * Created by zhi on 2015/4/24. */</span> <span class="hljs-keyword">public </span> <span class="hljs-class"><span class="hljs-keyword">class </span> <span class="hljs-title">outerclass </span> Span class= "hljs-keyword" >implements </span> <span class="hljs-title">view </span>. <span class="hljs-title">onclicklistener </span> { <span class="hljs-keyword">private </span> Activity act; Outerclass (activity Activity) {act = activity; } <span class="hljs-annotation"> @Override </span> <span class="hljs-keyword">public </span> <span class=" Hljs-keyword ">void </span> <span class=" hljs-title ">onclick </span> (View v) {toast.maketext (act,<span class=" hljs-st Ring ">" External class "</span>, toast.length_short). show (); }}</code></code></pre><p><p>Because the toast requires an activity parameter, you need to set this variable when building the class.<br>And when called, pass the arguments past:</p></p><pre class="prettyprint"><pre class="prettyprint"><code class=" hljs cs"><span class="hljs-comment">// 外部类</span> button3.setOnClickListener(<span class="hljs-keyword">new</span> OuterClass(<span class="hljs-keyword">this</span>));</code></pre></pre>Direct Binding Label<p><p>The direct binding tag refers to the settings in the XML file, as in the following example:</p></p><pre class="prettyprint"><pre class="prettyprint"><code class=" hljs applescript"> <Button android:layout_width=<span class="hljs-string">"wrap_content"</span> android:layout_height=<span class="hljs-string">"wrap_content"</span> android:<span class="hljs-type">text</span>=<span class="hljs-string">"Button4"</span> android:<span class="hljs-property">id</span>=<span class="hljs-string">"@+id/button4"</span> android:layout_below=<span class="hljs-string">"@+id/button3"</span> android:layout_alignStart=<span class="hljs-string">"@+id/button3"</span> android:onClick=<span class="hljs-string">"clickButton"</span>/></code></pre></pre><p><p>In the layout file, there is an onclick tag that formulates the function of the button binding.</p></p> <blockquote> <blockquote> <p><strong>tip:</strong> Here "clickbutton" is the function name to process the message, no parentheses are required</p> </blockquote> </blockquote><p><p>In The. Java file, write the Clickbutton method:</p></p><pre class="prettyprint"><pre class="prettyprint"><code class=" hljs cs"><span class="hljs-comment">// 直接绑定</span><span class="hljs-keyword">public</span><span class="hljs-keyword">void</span><span class="hljs-title">clickButton</span>(View source){ Toast.makeText(getApplicationContext(),<span class="hljs-string">"绑定标签"</span>, Toast.LENGTH_SHORT).show(); }</code></pre></pre> <blockquote> <blockquote> <p><strong>tip:</strong> It is important to note that the name of the function can be arbitrarily named, but the <strong>parameter</strong> must conform to this form (View Source) or the program will crash directly.</p> </blockquote> </blockquote>Summarize<p><p>This article is mainly about how the Android operating system to respond to events, this article is mainly to explain through the way of Listening.</p></p> <p><p>Listening-based Event response for Android development event response</p></p></span>