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   6         <title>eVaf Tutorial - 09 - GUI Module</title>
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  16         <h1>eVaf Tutorial</h1>
  17
  18         <h2>09 - GUI Module</h2>
  19
  20         <p>The Graphical User Interface (<tt>GUI</tt>) module implements the main window of the application. It uses previously
  21         created <tt>Generator</tt> and <tt>Storage</tt> modules to generate and store passwords.</p>
  22
  23         <p>We start by creating the <tt>gui.h</tt> file in the <tt>src/apps/PswGen/GUI</tt> directory:</p>
  24
  25         <pre class="hl"><span class="hl com">/**</span>
  26 <span class="hl com"> * &#64;file PswGen/GUI/gui.h</span>
  27 <span class="hl com"> */</span>
  28
  29 <span class="hl ppc">#ifndef __PSWGEN_GUI_GUI_H</span>
  30 <span class="hl ppc">#  define __PSWGEN_GUI_GUI_H</span>
  31
  32 <span class="hl ppc">#endif</span> <span class="hl slc">// gui.h</span><span class="hl ppc"></span></pre>
  33
  34         <p>Include the <tt>Plugins/iPlugin</tt> header file as this is going to be a plugin and also <tt>QObject</tt> and
  35         <tt>QString</tt> as these are almost always needed:</p>
  36
  37         <pre class="hl"><span class="hl ppc">#include &lt;Plugins/iPlugin&gt;</span>
  38 <span class="hl ppc">#include &lt;QObject&gt;</span>
  39 <span class="hl ppc">#include &lt;QString&gt;</span></pre>
  40
  41         <p>We use the <tt>eVaf::PswGen::GUI</tt> namespace for this module:</p>
  42
  43         <pre class="hl"><span class="hl kwa">namespace</span> eVaf <span class="hl opt">{</span>
  44 <span class="hl kwa">namespace</span> PswGen <span class="hl opt">{</span>
  45 <span class="hl kwa">namespace</span> GUI <span class="hl opt">{</span>
  46
  47 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::GUI</span>
  48 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen</span>
  49 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf</span></pre>
  50
  51         <p>The module itself can be implemented as one single class derived from the <tt>Plugins::iPlugin</tt> parent class:</p>
  52
  53         <pre class="hl"><span class="hl kwc">class</span> Module <span class="hl opt">:</span> <span class="hl kwc">public</span> Plugins<span class="hl opt">::</span>iPlugin
  54 <span class="hl opt">{</span>
  55     Q_OBJECT
  56
  57 <span class="hl kwc">public</span><span class="hl opt">:</span>
  58
  59     <span class="hl kwd">Module</span><span class="hl opt">();</span>
  60
  61     <span class="hl kwc">virtual</span> <span class="hl opt">~</span><span class="hl kwd">Module</span><span class="hl opt">();</span>
  62
  63 <span class="hl opt">};</span></pre>
  64
  65         <p>Implement pure virtual methods derived from the parent class. The main GUI window is created in the <tt>init()</tt> method
  66         and the module can only be ready when the initialization is completed. We use the <tt>mReady</tt> flag to indicate this.</p>
  67
  68         <pre class="hl">    <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">init</span><span class="hl opt">(</span><span class="hl kwb">const</span> QString <span class="hl opt">&amp;</span> args<span class="hl opt">);</span>
  69
  70     <span class="hl kwc">virtual</span> <span class="hl kwb">void</span> <span class="hl kwd">done</span><span class="hl opt">();</span>
  71
  72     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">isReady</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mReady<span class="hl opt">; }</span>
  73
  74 <span class="hl kwc">private</span><span class="hl opt">:</span>
  75
  76     <span class="hl kwb">bool</span> mReady<span class="hl opt">;</span></pre>
  77
  78         <p>In the private members section we store interfaces from previously written modules:</p>
  79
  80         <pre class="hl">
  81     eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iGenerator <span class="hl opt">*</span> mGenerator<span class="hl opt">;</span>
  82
  83     eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iStorage <span class="hl opt">*</span> mStorage<span class="hl opt">;</span></pre>
  84
  85         <p>Since these are not known yet, we also need to add forward declarations. These go into the <tt>eVaf::PswGen</tt> namespace
  86         at the beginning of the file:</p>
  87
  88         <pre class="hl">
  89 <span class="hl kwa">namespace</span> eVaf <span class="hl opt">{</span>
  90 <span class="hl kwa">namespace</span> PswGen <span class="hl opt">{</span>
  91     <span class="hl kwb">struct</span> iGenerator<span class="hl opt">;</span>
  92     <span class="hl kwb">struct</span> iStorage<span class="hl opt">;</span></pre>
  93
  94         <p>The main window needs couple of widgets on it:</p>
  95
  96         <ul>
  97             <li>Master password - a QLineEdit widget;</li>
  98             <li>Name of the password - a QLineEdit widget;</li>
  99             <li>Length of the password - a QSpinBox widget;</li>
 100             <li>Generated password - a QLineEdit widget that we make read-only;</li>
 101             <li>Generate button - a QPushButton widget;</li>
 102             <li>Copy button that copies generated passwords to the clipboard - a QPushButton widget.</li>
 103         </ul>
 104
 105         <pre class="hl">
 106     <span class="hl slc">/// Widgets on the screen</span>
 107     QLineEdit <span class="hl opt">*</span> wMasterPassword<span class="hl opt">;</span>
 108     QLineEdit <span class="hl opt">*</span> wName<span class="hl opt">;</span>
 109     QSpinBox <span class="hl opt">*</span> wLength<span class="hl opt">;</span>
 110     QLineEdit <span class="hl opt">*</span> wPassword<span class="hl opt">;</span>
 111     QPushButton <span class="hl opt">*</span> wGenerate<span class="hl opt">;</span>
 112     QPushButton <span class="hl opt">*</span> wCopy<span class="hl opt">;</span></pre>
 113
 114         <p>Add slots for push buttons:</p>
 115
 116         <pre class="hl"><span class="hl kwc">private</span> slots<span class="hl opt">:</span>
 117
 118     <span class="hl slc">/// 'Generate' button clicked</span>
 119     <span class="hl kwb">void</span> <span class="hl kwd">generateClicked</span><span class="hl opt">();</span>
 120
 121     <span class="hl slc">/// 'Copy' button clicked</span>
 122     <span class="hl kwb">void</span> <span class="hl kwd">copyClicked</span><span class="hl opt">();</span></pre>
 123
 124         <p>The <tt>private</tt> keyword is ignored by the Qt meta-object compiler, but it is a good practice to have it here
 125         as an indicator, that these slots are private and should not be used outside of the class.</p>
 126
 127         <p>The <tt>Generate</tt> push button should be enabled only when the master password and name are given. Add another
 128         slot that will be connected to the <tt>textChanged()</tt> signal from these widgets:</p>
 129
 130         <pre class="hl">
 131     <span class="hl slc">/// Master password or name changed</span>
 132     <span class="hl kwb">void</span> <span class="hl kwd">textChanged</span><span class="hl opt">(</span>QString <span class="hl kwb">const</span> <span class="hl opt">&amp;);</span></pre>
 133
 134         <p>And here is the final <tt>gui.h</tt> file:</p>
 135
 136         <pre class="hl"><span class="hl com">/**</span>
 137 <span class="hl com"> * &#64;file PswGen/GUI/gui.h</span>
 138 <span class="hl com"> */</span>
 139 <span class="hl ppc">#ifndef __PSWGEN_GUI_GUI_H</span>
 140 <span class="hl ppc">#  define __PSWGEN_GUI_GUI_H</span>
 141
 142 <span class="hl ppc">#include &lt;Plugins/iPlugin&gt;</span>
 143
 144 <span class="hl ppc">#include &lt;QObject&gt;</span>
 145 <span class="hl ppc">#include &lt;QString&gt;</span>
 146
 147 <span class="hl kwc">class</span> QLineEdit<span class="hl opt">;</span>
 148 <span class="hl kwc">class</span> QSpinBox<span class="hl opt">;</span>
 149 <span class="hl kwc">class</span> QPushButton<span class="hl opt">;</span>
 150
 151 <span class="hl kwa">namespace</span> eVaf <span class="hl opt">{</span>
 152 <span class="hl kwa">namespace</span> PswGen <span class="hl opt">{</span>
 153     <span class="hl kwb">struct</span> iGenerator<span class="hl opt">;</span>
 154     <span class="hl kwb">struct</span> iStorage<span class="hl opt">;</span>
 155 <span class="hl kwa">namespace</span> GUI <span class="hl opt">{</span>
 156
 157 <span class="hl com">/// Graphical User Interface for the PswGen application.</span>
 158 <span class="hl kwc">class</span> Module <span class="hl opt">:</span> <span class="hl kwc">public</span> Plugins<span class="hl opt">::</span>iPlugin
 159 <span class="hl opt">{</span>
 160     Q_OBJECT
 161
 162 <span class="hl kwc">public</span><span class="hl opt">:</span>
 163
 164     <span class="hl kwd">Module</span><span class="hl opt">();</span>
 165
 166     <span class="hl kwc">virtual</span> <span class="hl opt">~</span><span class="hl kwd">Module</span><span class="hl opt">();</span>
 167
 168     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">init</span><span class="hl opt">(</span><span class="hl kwb">const</span> QString <span class="hl opt">&amp;</span> args<span class="hl opt">);</span>
 169
 170     <span class="hl kwc">virtual</span> <span class="hl kwb">void</span> <span class="hl kwd">done</span><span class="hl opt">();</span>
 171
 172     <span class="hl kwc">virtual</span> <span class="hl kwb">bool</span> <span class="hl kwd">isReady</span><span class="hl opt">()</span> <span class="hl kwb">const</span> <span class="hl opt">{</span> <span class="hl kwa">return</span> mReady<span class="hl opt">; }</span>
 173
 174 <span class="hl kwc">private</span> slots<span class="hl opt">:</span>
 175
 176     <span class="hl slc">/// Master password or name changed</span>
 177     <span class="hl kwb">void</span> <span class="hl kwd">textChanged</span><span class="hl opt">(</span>QString <span class="hl kwb">const</span> <span class="hl opt">&amp;);</span>
 178
 179     <span class="hl slc">/// 'Generate' button clicked</span>
 180     <span class="hl kwb">void</span> <span class="hl kwd">generateClicked</span><span class="hl opt">();</span>
 181
 182     <span class="hl slc">/// 'Copy' button clicked</span>
 183     <span class="hl kwb">void</span> <span class="hl kwd">copyClicked</span><span class="hl opt">();</span>
 184
 185 <span class="hl kwc">private</span><span class="hl opt">:</span> <span class="hl slc">// Members</span>
 186
 187     <span class="hl kwb">static int const</span> DefaultPasswordLength<span class="hl opt">;</span>
 188
 189     <span class="hl slc">/// Flag indicating that the module is ready</span>
 190     <span class="hl kwb">bool</span> mReady<span class="hl opt">;</span>
 191
 192     <span class="hl slc">/// The iGenerator interface</span>
 193     eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iGenerator <span class="hl opt">*</span> mGenerator<span class="hl opt">;</span>
 194
 195     <span class="hl slc">/// The iStorage interface (can be null)</span>
 196     eVaf<span class="hl opt">::</span>PswGen<span class="hl opt">::</span>iStorage <span class="hl opt">*</span> mStorage<span class="hl opt">;</span>
 197
 198     <span class="hl slc">/// Widgets on the screen</span>
 199     QLineEdit <span class="hl opt">*</span> wMasterPassword<span class="hl opt">;</span>
 200     QLineEdit <span class="hl opt">*</span> wName<span class="hl opt">;</span>
 201     QSpinBox <span class="hl opt">*</span> wLength<span class="hl opt">;</span>
 202     QLineEdit <span class="hl opt">*</span> wPassword<span class="hl opt">;</span>
 203     QPushButton <span class="hl opt">*</span> wGenerate<span class="hl opt">;</span>
 204     QPushButton <span class="hl opt">*</span> wCopy<span class="hl opt">;</span>
 205 <span class="hl opt">};</span>
 206
 207 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen::GUI</span>
 208 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf::PswGen</span>
 209 <span class="hl opt">}</span> <span class="hl slc">// namespace eVaf</span>
 210
 211 <span class="hl ppc">#endif</span> <span class="hl slc">// gui.h</span><span class="hl ppc"></span>
 212 </pre>
 213
 214         <p>Continue implementing the <a href="pswgen10.html">GUI Module</a>.</p>
 215
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