我是Java的初学者，我遇到了问题。
我<form role="form" action="contactttry.php" class="contact-form" id="contact-form" method="post">
<div class="form-group">
<select class="form-control" id="se1" NAME="section" onChange="SelectRedirect();">
<Option value="">Select Section</option>
<Option value="PHP">PHP</option>
<Option value="ASP">ASP</option>
<Option value="MySQL">MySQL</option>
<Option value="JS">JavaScript</option>
<Option value="HTML">HTML</option>
</select>
</div>
<div class="form-group">
<div class="controls">
<input type="text" placeholder="Name" name="name" id="name" required>
</div>
</div>
<div class="form-group">
<div class="controls">
<input type="email" class="email" placeholder="Email" name="email" id="email" required >
</div>
</div>
<div class="form-group">
<div class="controls">
<input type="text" class="requiredField" placeholder="Mobile No." name="phone" id="phone" required>
</div>
</div>
<button type="submit" id="submit" class="btn-system btn-large" >Submit</button>
<div id="success" style="color:#34495e;"></div>
</form>
<!-- End Contact Form -->调用了JFrame，它有两个按钮。这是我的听众代码：
chooseMenu然后从 private void btnNutrisiBahanActionPerformed(java.awt.event.ActionEvent evt) {
mainPanel = new FoodSourceNutrition();
mainPanel.repaint();
mainScrol.setViewportView(mainPanel);
mainPanel.setAutoscrolls(true);
}
private void btnRekomendasiActionPerformed(java.awt.event.ActionEvent evt) {
mainPanel = new Recommendation();
mainPanel.repaint();
mainScrol.setViewportView(mainPanel);
mainPanel.setAutoscrolls(true);
}
我想使用后退按钮回到FoodSourceNutrition，但似乎我不能这样做：
chooseMenu如何从框架中打开另一个框架？