Android APP: BlackContact 显示黑名单联络人信息
有别于前面利用 fragment 实现，这次利用单纯的 activity 来实现：
首先定义主画面LAYOUT， 有Title，分隔线 activity_main.xml
由于分割线有特别的 Stytle 所以另外再定义 stytles.xml
而养成良好的习惯将用到的字串定义在 strings.xml
BlackContact
通讯卫士
Hello world!
Settings
黑名单管理
添加
黑名单记录为空
在画面处理好之后，处理 activity_main.xml 中 listview, 每一列的显示 LAYOUT， 用另外一个 custom.xml 来定义:
接着开始编写数据库的读取 - BlackInfoDBHelper.java
/**
* Created by elvis on 10/14/15.
*/
package com.elvis.android.blackcontacts;
import android.content.Context;
import android.database.Cursor;
import android.database.SQLException;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteDatabase.CursorFactory;
import android.database.sqlite.SQLiteOpenHelper;
import android.util.Log;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
public class BlackInfoDBHelper extends SQLiteOpenHelper {
private final static String DATABASE_NAME = "econtacts.db";
private final static int DATABASE_VERSION = 1;
private static final String DATABASE_PATH = "/data/data/com.elvis.android.blackcontacts" +
"/databases/";
private static final String TABLE_CONTACT = "contact_info";
private static SQLiteDatabase mDataBase;
private static final String KEY_ID = "serialno";
private static final String KEY_NAME = "name";
private static final String KEY_ALIAS = "alias";
private static final String KEY_PH1 = "phone1";
private static final String KEY_PH2 = "phone2";
private static final String KEY_REMARK = "remark";
private static String TAG = "BlackInfoDBHelper";
private static Context context = null;
public BlackInfoDBHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
try {
//Log.i(TAG, "OK");
this.context = context;
createDataBase();
openDataBase();
} catch (IOException e) {
e.printStackTrace();
}
}
@Override
public void onCreate(SQLiteDatabase db) {
// TODO Auto-generated method stub
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
/* TODO Auto-generated method stub */
}
private boolean checkDataBase() {
File dbFile;
dbFile = context.getDatabasePath(DATABASE_NAME);
return dbFile.exists();
}
private void createDataBase() throws IOException {
boolean dbExist = checkDataBase();
if (dbExist) {
} else {
// By calling this method an empty database will be created into
// the default system path
// of your application so we are gonna be able to overwrite that
// database with our database.
this.getReadableDatabase();
this.close();
try {
copyDataBase();
Log.i(TAG, "Database was created");
} catch (IOException e) {
throw new Error("Error copying database");
}
}
}
private void openDataBase() throws SQLException {
// Open the database
String myPath = DATABASE_PATH + DATABASE_NAME;
Log.i(TAG, "DB_PATH = "+ myPath);
mDataBase = SQLiteDatabase.openDatabase(myPath, null,
SQLiteDatabase.OPEN_READWRITE);
}
@Override
public synchronized void close() {
if (mDataBase != null)
mDataBase.close();
super.close();
}
public void copyDataBase() throws IOException {
// Open your local db as the input stream
//InputStream myInput = ApplicationContextProvider.getContext().getAssets().open(DATABASE_NAME);
InputStream myInput = context.getAssets().open(DATABASE_NAME);
// Path to the just created empty db
String outFileName = DATABASE_PATH + DATABASE_NAME;
// Open the empty db as the output stream
OutputStream myOutput = new FileOutputStream(outFileName);
// transfer bytes from the inputfile to the outputfile
byte[] buffer = new byte[1024];
int length;
while ((length = myInput.read(buffer)) > 0) {
myOutput.write(buffer, 0, length);
}
// Close the streams
myOutput.flush();
myOutput.close();
myInput.close();
}
public ArrayList select(String query) throws SQLException {
//Cursor c=null;
ArrayList objects = new ArrayList();
Log.i(TAG, "SQL Command = " + query);
Cursor c=null;
try {
c = mDataBase.rawQuery(query, null);
int id[]=new int[c.getCount()];
int i=0;
if (c.getCount() > 0)
{
c.moveToFirst();
do {
id[i]=c.getInt(c.getColumnIndex("name"));
Log.i(TAG, "Name: " + c.getString(1));
i++;
Contacts cons = new Contacts(c.getString(1), c.getString(2),
c.getString(3), c.getString(4), c.getString(5));
objects.add(cons);
//cursor = c;
} while (c.moveToNext());
c.close();
}
} catch (Exception e) {
c.close();
} finally {
if(c!=null) {
c.close();
}
}
c.close();
return objects;
}
}
1. 检查 app databases 下有没有 econtacts.db 存在, 若无则复制 econtacts.db 到 app databases 下
2. 实现 contact_info 所有的查询结果, 并返回到一个叫 Contacts 的阵列.
所以我们需要定义 Contacts.java
package com.elvis.android.blackcontacts;
/**
* Created by elvis on 10/15/15.
*/
public class Contacts {
private String name="";
private String alias="";
private String phone1="";
private String phone2="";
private String remark="";
public void setName(String name) {
this.name = name;
}
public String getName() {
return this.name;
}
public String getAlias() {
return this.alias;
}
public void setAlias(String alias) {
this.alias = alias;
}
public String getPhone1() {
return this.phone1;
}
public void setPhone1(String phone) {
this.phone1 = phone;
}
public String getPhone2() {
return this.phone2;
}
public void setPhone2(String phone) {
this.phone2 = phone;
}
public String getRemark() {
return this.remark;
}
public void setRemark(String remark) {
this.remark = remark;
}
public Contacts (String name,String alias, String ph1,String ph2, String remark){
this.name = name;
this.alias = alias;
this.phone1 = ph1;
this.phone2 = ph2;
this.remark = remark;
}
public Contacts (){
}
}
之后再编写 Adapter 类用来定义 lv_blackinfo 与 Contacts 列表的关系: BlackInfoAdapter.java
package com.elvis.android.blackcontacts;
import android.widget.BaseAdapter;
import java.util.ArrayList;
import android.view.LayoutInflater;
import android.content.Context;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
/**
* Created by elvis on 10/16/15.
*/
public class BlackInfoAdapter extends BaseAdapter {
private static ArrayList searchArrayList;
private LayoutInflater mInflater;
public BlackInfoAdapter(Context context, ArrayList results) {
searchArrayList = results;
mInflater = LayoutInflater.from(context);
}
public int getCount() {
return searchArrayList.size();
}
public Object getItem(int position) {
return searchArrayList.get(position);
}
public long getItemId(int position) {
return position;
}
@Override
public View getView(int position, View convertView, ViewGroup parent) {
View row;
row = mInflater.inflate(R.layout.custom, parent, false);
TextView tv_name, tv_alias, tv_phone1, tv_phone2, tv_remark;
tv_name = (TextView) row.findViewById(R.id.tv_name);
tv_alias = (TextView) row.findViewById(R.id.tv_alias);
tv_phone1 = (TextView) row.findViewById(R.id.tv_phone1);
tv_phone2 = (TextView) row.findViewById(R.id.tv_phone2);
tv_remark = (TextView) row.findViewById(R.id.tv_remark);
tv_name.setText(searchArrayList.get(position).getName());
tv_alias.setText(searchArrayList.get(position).getAlias());
tv_phone1.setText(searchArrayList.get(position).getPhone1());
tv_phone2.setText(searchArrayList.get(position).getPhone2());
tv_remark.setText(searchArrayList.get(position).getRemark());
tv_phone1.setVisibility(row.GONE);
tv_phone2.setVisibility(row.GONE);
return (row);
}
}
由于所占的版面较大， 所以将电话的部分先隐藏.
最后可以开始完成主程式 MainActivity.java 的编写
package com.elvis.android.blackcontacts;
import android.app.Activity;
import android.os.Bundle;
import android.view.Menu;
import android.view.MenuItem;
import android.view.View.OnClickListener;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
import android.widget.ListView;
import android.content.Context;
import java.util.ArrayList;
public class MainActivity extends Activity implements OnClickListener{
//public class MainActivity extends ListActivity{
private TextView tv_add_blackinfo;
private ListView lv_blackinfo;
private TextView tv_empty_blackinfo;
private BlackInfoDBHelper dbhelper = null;
private static final String TABLE_NAME = "contact_info";
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
tv_add_blackinfo = (TextView) findViewById(R.id.tv_add_blackinfo);
tv_add_blackinfo.setOnClickListener(this);
lv_blackinfo = (ListView)findViewById(R.id.lv_blackinfo);
tv_empty_blackinfo = (TextView) findViewById(R.id.tv_empty_blackinfo);
lv_blackinfo.setEmptyView(tv_empty_blackinfo);
Context context = getApplicationContext();
dbhelper = new BlackInfoDBHelper(context);
ArrayList objects = dbhelper.select("SELECT * FROM " + TABLE_NAME);
BlackInfoAdapter customAdapter = new BlackInfoAdapter(context, objects);
lv_blackinfo.setAdapter(customAdapter);
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
public void onClick(View v) {
int id = v.getId();
switch(id) {
case R.id.tv_add_blackinfo:
Toast.makeText(this, "点击添加", Toast.LENGTH_LONG).show();
break;
}
}
} 执行结果：
此时可以对 econtacts.db 中的 contact_info 内容作检查:
结果是吻合的!!
在编写 activity 的过程中， 有发生一段小插曲, 错误提示: "manifest file doesn't end with a final newline". 一直找不到原因.
语法检查也没有错误. 后来在一次偶然的操作， 这错误提示就消失了, 而这个简单的动作， 就是往上移动滑鼠游标，就解决问题.
以下图例说明， 会出现错误的情形（此时游标在图白的位置）。 红底色的地方就是提示错误的地方.
可是当游标移动到下图白色位置， 错误提示消失, 问题解决.
再添个小插曲, 模拟器有时侯执行太久记忆体错乱， 需重置模拟器做法如下:
