35.Android之带删除按钮EditText学习

今天实现Android里自定义带删除功能的EditText，效果如下：

当输入内容时，EditText变为带有一个删除功能按钮的编辑框，如图：

实现代码很简单，直接上代码,

布局文件xml:

 1 <?xml version="1.0" encoding="utf-8"?>
 2 <LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
 3     android:layout_width="match_parent"
 4     android:layout_height="match_parent"
 5     android:background="#000000"
 6     android:orientation="vertical" >
 7 
 8     <LinearLayout
 9         android:layout_width="match_parent"
10         android:layout_height="wrap_content"
11         android:background="@drawable/back" 
12         android:layout_marginBottom="5dp"
13         android:layout_marginLeft="5dp"
14         android:layout_marginRight="5dp"
15         android:layout_marginTop="5dp" >
16 
17         <ImageView
18             android:id="@+id/search_img"
19             android:layout_width="wrap_content"
20             android:layout_height="wrap_content"
21             android:paddingTop="7dp"
22             android:src="@drawable/search" />
23 
24         <EditText
25             android:id="@+id/clearText"
26             android:layout_width="fill_parent"
27             android:layout_height="wrap_content"
28             android:layout_weight="1"
29             android:background="@null"
30             android:hint="搜索"
31             android:imeOptions="actionDone"
32             android:singleLine="true" >
33         </EditText>
34 
35         <Button
36             android:id="@+id/clear_btn"
37             android:layout_width="40dp"
38             android:layout_height="40dp"
39             android:background="@drawable/clear" />
40     </LinearLayout>
41 
42 </LinearLayout>

activity代码：

 1 package com.example.cleartextdemo;
 2 
 3 import android.app.Activity;
 4 import android.os.Bundle;
 5 import android.text.Editable;
 6 import android.text.TextWatcher;
 7 import android.view.View;
 8 import android.widget.Button;
 9 import android.widget.EditText;
10 
11 public class MainActivity extends Activity {
12 
13     private EditText clearEditText;
14     private Button clearbtn;
15 
16     @Override
17     protected void onCreate(Bundle savedInstanceState) {
18         super.onCreate(savedInstanceState);
19         setContentView(R.layout.activity_main);
20 
21         clearEditText = (EditText) findViewById(R.id.clearText);
22         clearbtn = (Button) findViewById(R.id.clear_btn);
23         clearbtn.setOnClickListener(new View.OnClickListener() {
24             @Override
25             public void onClick(View v) {
26                 clearEditText.setText("");
27             }
28         });
29 
30         clearEditText.addTextChangedListener(mTextWatcher);
31 
32     }
33 
34     TextWatcher mTextWatcher = new TextWatcher() {
35 
36         @Override
37         public void beforeTextChanged(CharSequence s, int start, int count,
38                 int after) {
39             // TODO Auto-generated method stub
40 
41         }
42 
43         @Override
44         public void onTextChanged(CharSequence s, int start, int before,
45                 int count) {
46             // TODO Auto-generated method stub
47 
48         }
49 
50         @Override
51         public void afterTextChanged(Editable s) {
52             if (clearEditText.getText().toString() != null
53                     && !clearEditText.getText().toString().equals("")) {
54                 clearbtn.setVisibility(View.VISIBLE);
55             } else {
56                 clearbtn.setVisibility(View.INVISIBLE);
57             }
58 
59         }
60 
61     };
62 
63 }

运行后输入信息如图：

按下删除控件变为：