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:

<?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="match_parent"
    android:background="#000000"
    android:orientation="vertical" >

    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:background="@drawable/back" 
        android:layout_marginBottom="5dp"
        android:layout_marginLeft="5dp"
        android:layout_marginRight="5dp"
        android:layout_marginTop="5dp" >

        <ImageView
            android:id="@+id/search_img"
            android:layout_width="wrap_content"
            android:layout_height="wrap_content"
            android:paddingTop="7dp"
            android:src="@drawable/search" />

        <EditText
            android:id="@+id/clearText"
            android:layout_width="fill_parent"
            android:layout_height="wrap_content"
            android:layout_weight="1"
            android:background="@null"
            android:hint="搜索"
            android:imeOptions="actionDone"
            android:singleLine="true" >
        </EditText>

        <Button
            android:id="@+id/clear_btn"
            android:layout_width="40dp"
            android:layout_height="40dp"
            android:background="@drawable/clear" />
    </LinearLayout>

</LinearLayout>

activity代码：

package com.example.cleartextdemo;

import android.app.Activity;
import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;

public class MainActivity extends Activity {

    private EditText clearEditText;
    private Button clearbtn;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        clearEditText = (EditText) findViewById(R.id.clearText);
        clearbtn = (Button) findViewById(R.id.clear_btn);
        clearbtn.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                clearEditText.setText("");
            }
        });

        clearEditText.addTextChangedListener(mTextWatcher);

    }

    TextWatcher mTextWatcher = new TextWatcher() {

        @Override
        public void beforeTextChanged(CharSequence s, int start, int count,
                int after) {
            // TODO Auto-generated method stub

        }

        @Override
        public void onTextChanged(CharSequence s, int start, int before,
                int count) {
            // TODO Auto-generated method stub

        }

        @Override
        public void afterTextChanged(Editable s) {
            if (clearEditText.getText().toString() != null
                    && !clearEditText.getText().toString().equals("")) {
                clearbtn.setVisibility(View.VISIBLE);
            } else {
                clearbtn.setVisibility(View.INVISIBLE);
            }

        }

    };

}

 运行后输入信息如图：

按下删除控件变为：