使用autoCompleteTextView读取历史记录

package org.yaoming.read_his; import android.app.Activity; import android.content.SharedPreferences; import android.os.Bundle; import android.util.Log; import android.view.View; import android.view.View.OnClickListener; import android.view.View.OnFocusChangeListener; import android.widget.ArrayAdapter; import android.widget.AutoCompleteTextView; import android.widget.Button; public class Read_historyActivity extends Activity implements OnClickListener { private AutoCompleteTextView autoTv; /** Called when the activity is first created. */ @Override public void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.main); autoTv = (AutoCompleteTextView) findViewById(R.id.autoCompleteTextView1); initAutoComplete("history",autoTv); Button search = (Button) findViewById(R.id.button1); search.setOnClickListener(this); } @Override public void onClick(View v) { // 这里可以设定：当搜索成功时，才执行保存操作 saveHistory("history",autoTv); } /** * 初始化AutoCompleteTextView，最多显示5项提示，使 * AutoCompleteTextView在一开始获得焦点时自动提示 * @param field 保存在sharedPreference中的字段名 * @param auto 要操作的AutoCompleteTextView */ private void initAutoComplete(String field,AutoCompleteTextView auto) { SharedPreferences sp = getSharedPreferences("network_url", 0); String longhistory = sp.getString("history", "nothing"); String[] hisArrays = longhistory.split(","); ArrayAdapter<String> adapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, hisArrays); //只保留最近的50条的记录 if(hisArrays.length > 50){ String[] newArrays = new String[50]; System.arraycopy(hisArrays, 0, newArrays, 0, 50); adapter = new ArrayAdapter<String>(this, android.R.layout.simple_dropdown_item_1line, newArrays); } auto.setAdapter(adapter); auto.setDropDownHeight(350); auto.setThreshold(1); auto.setCompletionHint("最近的5条记录"); auto.setOnFocusChangeListener(new OnFocusChangeListener() { @Override public void onFocusChange(View v, boolean hasFocus) { AutoCompleteTextView view = (AutoCompleteTextView) v; if (hasFocus) { view.showDropDown(); } } }); } /** * 把指定AutoCompleteTextView中内容保存到sharedPreference中指定的字符段 * @param field 保存在sharedPreference中的字段名 * @param auto 要操作的AutoCompleteTextView */ private void saveHistory(String field,AutoCompleteTextView auto) { String text = auto.getText().toString(); SharedPreferences sp = getSharedPreferences("network_url", 0); String longhistory = sp.getString(field, "nothing"); if (!longhistory.contains(text + ",")) { StringBuilder sb = new StringBuilder(longhistory); sb.insert(0, text + ","); sp.edit().putString("history", sb.toString()).commit(); } } }