Android Toast 简单分析

   <h3>介绍</h3>    <p>A toast provides simple feedback about an operation in a small popup. It only fills the amount of</p>    <p>space required for the message and the current activity remains visible and interactive. For</p>    <p>example, navigating away from an email before you send it triggers a “Draft saved” toast to let</p>    <p>you know that you can continue editing later. Toasts automatically disappear after a timeout.</p>    <p>翻译：</p>    <p>Toast以一种小弹框的方式来给予用户反馈，它只需要消息可以显示出来的那小部分空间，同时Activity依</p>    <p>然可见可交互。例如，当你写邮件的时候退出，会触发“草稿已保存”的Toast来让你知道你以后可以继续</p>    <p>编辑这封邮件。Toast会在一段时间后自己消失。</p>    <p style="text-align:center"><img src="https://simg.open-open.com/show/dc9d3e5395833eab8c48e32dcb4100b1.png"></p>    <h3>类结构</h3>    <p>Toast的成员</p>    <p style="text-align:center"><img src="https://simg.open-open.com/show/dab17b994c1a9cd9b88758bee4334f9c.png"></p>    <p>成员解释</p>    <table>     <thead>      <tr>       <th>成员</th>       <th>含义</th>      </tr>     </thead>     <tbody>      <tr>       <td>Toast(Context)</td>       <td>构造函数</td>      </tr>      <tr>       <td>show()</td>       <td>显示Toast</td>      </tr>      <tr>       <td>cancel()</td>       <td>取消Toast</td>      </tr>      <tr>       <td>setMargin(float,float)</td>       <td>设置横向的margin和纵向的margin</td>      </tr>      <tr>       <td>setGravity(int ,int, int)</td>       <td>设置toast的位置重心和相对的XOffset, YOffset</td>      </tr>      <tr>       <td>makeText(Context, CharSequence, int)</td>       <td>利用字符串创建Toast</td>      </tr>      <tr>       <td>makeText(Context, int, int)</td>       <td>利用字符串资源创建Toast</td>      </tr>      <tr>       <td>setView(View)</td>       <td>设置自定义Toast显示的View</td>      </tr>      <tr>       <td>setDuration(int)</td>       <td>设置Toast的显示时间</td>      </tr>      <tr>       <td>setText</td>       <td>设置Message文本内容</td>      </tr>      <tr>       <td>备注：</td>       <td>部分getter方法和setter方法对应，没有写入</td>      </tr>     </tbody>    </table>    <h3>实际使用</h3>    <p><em>布局文件</em> activity_main.xml</p>    <pre>  <code class="language-java"><?xml version="1.0" encoding="utf-8"?>  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"      xmlns:tools="http://schemas.android.com/tools"      android:layout_width="match_parent"      android:layout_height="match_parent"      android:orientation="vertical"      android:paddingBottom="@dimen/activity_vertical_margin"      android:paddingLeft="@dimen/activity_horizontal_margin"      android:paddingRight="@dimen/activity_horizontal_margin"      android:paddingTop="@dimen/activity_vertical_margin"      tools:context="mraz.com.toastdemo.MainActivity">        <Button          android:id="@+id/bt_simple"          android:layout_width="match_parent"          android:layout_height="wrap_content"          android:background="@color/colorAccent"          android:text="Simple Toast" />        <Button          android:id="@+id/bt_custom"          android:layout_width="match_parent"          android:layout_height="wrap_content"          android:layout_marginTop="30dp"          android:background="@color/colorPrimary"          android:text="Custom Toast" />  </LinearLayout></code></pre>    <p>自定义的Toast布局</p>    <p>custom_toast.xml</p>    <pre>  <code class="language-java"><?xml version="1.0" encoding="utf-8"?>  <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"      android:layout_width="match_parent"      android:layout_height="40dp"      android:background="@drawable/shape_bg"      android:orientation="horizontal">        <ImageView          android:layout_width="40dp"          android:layout_height="40dp"          android:src="@drawable/ic_account_circle_black_24dp" />        <TextView          android:layout_width="wrap_content"          android:layout_height="40dp"          android:layout_marginLeft="10dp"          android:layout_marginRight="10dp"          android:gravity="center"          android:text="This is a Custom Toast !"          android:textStyle="italic" />  </LinearLayout></code></pre>    <p>代码内容</p>    <pre>  <code class="language-java">package mraz.com.toastdemo;    import android.content.Context;  import android.os.Bundle;  import android.support.v7.app.AppCompatActivity;  import android.view.Gravity;  import android.view.LayoutInflater;  import android.view.View;  import android.widget.Button;  import android.widget.Toast;    public class MainActivity extends AppCompatActivity implements View.OnClickListener {        Context mContext;      Button btSimple, btCustom;        @Override      protected void onCreate(Bundle savedInstanceState) {          super.onCreate(savedInstanceState);          setContentView(R.layout.activity_main);            mContext = this;            btSimple = (Button) findViewById(R.id.bt_simple);          btCustom = (Button) findViewById(R.id.bt_custom);            btSimple.setOnClickListener(this);          btCustom.setOnClickListener(this);        }        @Override      public void onClick(View view) {          switch (view.getId()) {              case R.id.bt_simple:                  Toast.makeText(mContext, " This is a simple toast", Toast.LENGTH_SHORT).show();                  break;              case R.id.bt_custom:                  LayoutInflater layoutInflater = LayoutInflater.from(mContext);                  View custToast = layoutInflater.inflate(R.layout.custom_toast, null);                  Toast toast = new Toast(mContext);                  toast.setView(custToast);                  toast.setDuration(Toast.LENGTH_SHORT);                  toast.setGravity(Gravity.CENTER_VERTICAL, 0, 0);                  toast.show();                  break;          }      }  }</code></pre>    <h3>实际效果</h3>    <p style="text-align:center"><img src="https://simg.open-open.com/show/6e8e7c90fed9a065c8dd2a7f6f339044.gif"></p>    <h3>备注</h3>    <p>Toast的内容比较简单，但是开发过程中应该会经常用到，说不定偶尔还会碰到显示不出来的情况，不要忘记执行show()方法，当然，还有可能是其他的原因导致你的Toast无法显示~</p>    <p> </p>    <p>来自：http://blog.csdn.net/poorkick/article/details/51842700</p>    <p> </p>