import android.os.Bundle;
import android.text.Editable;
import android.text.TextWatcher;
import android.view.KeyEvent;
import android.view.View;
import android.view.View.OnClickListener;
import android.view.View.OnKeyListener;
import android.widget.Button;
import android.widget.EditText;
import android.widget.LinearLayout;
import android.widget.Toast;
import android.app.Activity;

public class MainActivity extends Activity {

	private EditText mEtSearch = null;// 输入搜索内容
	private Button mBtnClearSearchText = null;// 清空搜索信息的按钮
	private LinearLayout mLayoutClearSearchText = null;

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

		mEtSearch = (EditText) findViewById(R.id.et_search);
		mBtnClearSearchText = (Button) findViewById(R.id.btn_clear_search_text);
		mLayoutClearSearchText = (LinearLayout) findViewById(R.id.layout_clear_search_text);
		mEtSearch.addTextChangedListener(new TextWatcher() {

			@Override
			public void onTextChanged(CharSequence s, int start, int before,
					int count) {

			}

			@Override
			public void beforeTextChanged(CharSequence s, int start, int count,
					int after) {
			}

			@Override
			public void afterTextChanged(Editable s) {
				int textLength = mEtSearch.getText().length();
				if (textLength > 0) {
					mLayoutClearSearchText.setVisibility(View.VISIBLE);
				} else {
					mLayoutClearSearchText.setVisibility(View.GONE);
				}
			}
		});

		mBtnClearSearchText.setOnClickListener(new OnClickListener() {
			@Override
			public void onClick(View v) {
				mEtSearch.setText("");
				mLayoutClearSearchText.setVisibility(View.GONE);
			}
		});
		mEtSearch.setOnKeyListener(new OnKeyListener() {

			@Override
			public boolean onKey(View arg0, int keyCode, KeyEvent event) {
				if (keyCode == KeyEvent.KEYCODE_ENTER) {
					Toast.makeText(MainActivity.this,
							mEtSearch.getText().toString().trim(),
							Toast.LENGTH_LONG).show();
				}
				return false;
			}
		});
	}

}

布局文件

<LinearLayout  xmlns:android="http://schemas.android.com/apk/res/android"
    android:layout_width="fill_parent"
    android:layout_height="fill_parent"
 	 android:orientation="vertical">


    <LinearLayout 
    android:layout_width="fill_parent"
    android:layout_height="50dp"
    android:layout_marginTop="5dp"
    android:layout_marginLeft="20dp"
    android:layout_marginRight="12dp"
    android:background="@drawable/shape_search_app_bg_yj"
    android:orientation="horizontal">
        
        <!-- 输入的搜索信息 -->
       <EditText
        android:id="@+id/et_search"
        android:layout_weight="4"
        android:layout_width="0dp"
        android:layout_height="fill_parent"
        android:imeOptions="actionSearch"
        android:layout_marginLeft="10dp"
        android:textColor="#0e0e0e"
        android:textSize="17sp"
        android:singleLine="true"
        android:hint="搜索"
        android:textColorHint="#b0c6ce"
        android:gravity="center_vertical"
        android:drawableLeft="@drawable/ic_search_app_left"
        android:background="@null"/>
       
       
       <!-- 清空搜索文字按钮 -->
       <LinearLayout 
           android:id="@+id/layout_clear_search_text"
           android:layout_weight="0.5"
           android:layout_width="0dp"
           android:layout_height="fill_parent"
           android:visibility="gone"
           android:orientation="horizontal">
       <Button 
           android:id="@+id/btn_clear_search_text"
           android:layout_width="wrap_content"
           android:layout_height="wrap_content"
           android:layout_gravity="right|center_vertical"
           android:background="@drawable/selector_btn_search_clear_text_right"
         />
        </LinearLayout>
    </LinearLayout>
    
    
</LinearLayout>