小Y学习andrpid点滴记录一：使用adapter小练习

在做项目的时候，刚开始经常会看到要单独写adapter，可是不怎么会用也不怎么明白。就在网上找了一个例子，写了一下。希望能有帮助。

activity_main.xml<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"    xmlns:tools="http://schemas.android.com/tools"    android:layout_width="match_parent"    android:layout_height="match_parent"    android:orientation="vertical"    tools:context=".MainActivity"><LinearLayout    android:layout_width="match_parent"    android:layout_height="wrap_content"    android:orientation="horizontal">    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/text"        android:text="文字"/>    <Button        android:layout_width="wrap_content"        android:layout_height="wrap_content"        android:id="@+id/Add"        android:text="添加"/>    </LinearLayout>    <ListView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:id="@+id/list">        </ListView></LinearLayout>

addcontent.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:orientation="vertical">    <!--android:visibility="gone"设置为隐藏-->    <EditText        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:layout_weight="1"        android:background="@null"        android:gravity="top"        android:id="@+id/ettext"        android:hint="有了记事本，我再也不会忘记事情了"/>    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal">        <Button            android:id="@+id/save"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_weight="1"            android:text="保存"/>        <Button            android:id="@+id/delete"            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:layout_weight="1"            android:text="取消"/>        </LinearLayout></LinearLayout>

cell.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:orientation="vertical">    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal">        <LinearLayout            android:layout_width="match_parent"            android:layout_height="100dp"            android:gravity="center_vertical"            android:orientation="vertical">            <TextView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:id="@+id/list_content"                android:text="tv"/>            <TextView                android:layout_width="wrap_content"                android:layout_height="wrap_content"                android:id="@+id/list_time"                android:text="tv"/>            </LinearLayout>        </LinearLayout></LinearLayout>

select.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:orientation="vertical">    <TextView        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:id="@+id/s_tv"        android:layout_weight="1"/>    <LinearLayout        android:layout_width="match_parent"        android:layout_height="wrap_content"        android:orientation="horizontal">        <Button            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="删除"            android:id="@+id/s_delete"            android:layout_weight="1"/>        <Button            android:layout_width="wrap_content"            android:layout_height="wrap_content"            android:text="返回"            android:id="@+id/s_back"            android:layout_weight="1"/>        </LinearLayout></LinearLayout>

MainActivity.java

package com.example.admin_pc.adapter;import android.app.Activity;import android.content.ContentValues;import android.content.Intent;import android.database.Cursor;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.AdapterView;import android.widget.AdapterView.OnItemClickListener;import android.widget.Button;import android.widget.ListView;import java.text.SimpleDateFormat;import java.util.Date;public class MainActivity extends Activity  {    private Button textbtn,AddBtn;    private ListView lv;    private MyAdapter adapter;    private NotesDB notesDB;    private SQLiteDatabase dbReader;    private SQLiteDatabase dbWriter;    private Cursor cursor;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);        initView();    }    public void initView() {        lv = (ListView) findViewById(R.id.list);        textbtn = (Button) findViewById(R.id.text);        AddBtn = (Button) findViewById(R.id.Add);        notesDB = new NotesDB(this);        dbReader = notesDB.getReadableDatabase();        dbWriter = notesDB.getWritableDatabase();        lv.setOnItemClickListener(new OnItemClickListener() {            @Override            public void onItemClick(AdapterView<?> parent, View view,                                    int position, long id) {                cursor.moveToPosition(position);                Intent i = new Intent(MainActivity.this, SelectActivity.class);                i.putExtra(NotesDB.ID,                        cursor.getInt(cursor.getColumnIndex(NotesDB.ID)));                i.putExtra(NotesDB.CONTENT, cursor.getString(cursor                        .getColumnIndex(NotesDB.CONTENT)));                i.putExtra(NotesDB.TIME,                        cursor.getString(cursor.getColumnIndex(NotesDB.TIME)));                startActivity(i);            }        });        textbtn.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                Intent i = new Intent(MainActivity.this, AddContent.class);                startActivity(i);            }        });        AddBtn.setOnClickListener(new OnClickListener() {            @Override            public void onClick(View v) {                addDB();                selectDB();            }        });    }    public void selectDB() {        cursor = dbReader.query(NotesDB.TABLE_NAME, null, null, null, null,                null, null);        adapter = new MyAdapter(this, cursor);        lv.setAdapter(adapter);    }    @Override    protected void onResume() {        super.onResume();        selectDB();    }    public void addDB() {        ContentValues cv = new ContentValues();        cv.put(NotesDB.TIME, getTime());        cv.put(NotesDB.CONTENT, "Add添加内容");        dbWriter.insert(NotesDB.TABLE_NAME, null, cv);    }    private String getTime() {        SimpleDateFormat format = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");        Date curDate = new Date();        String str = format.format(curDate);        return str;    }}

SelectActivity.java

package com.example.admin_pc.adapter;import android.app.Activity;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.View;import android.widget.Button;import android.widget.TextView;/** * Created by Admin-PC on 2015/3/2. * */public class SelectActivity extends Activity implements View.OnClickListener {    private Button s_delete, s_back;    private TextView s_tv;    private NotesDB notesDB;    private SQLiteDatabase dbWriter;    @Override    protected void onCreate(Bundle savedInstanceState) {        // TODO Auto-generated method stub        super.onCreate(savedInstanceState);        setContentView(R.layout.select);        // System.out.println(getIntent().getIntExtra(NotesDB.ID, 0));        s_delete = (Button) findViewById(R.id.s_delete);        s_back = (Button) findViewById(R.id.s_back);        s_tv = (TextView) findViewById(R.id.s_tv);        notesDB = new NotesDB(this);        dbWriter = notesDB.getWritableDatabase();        s_back.setOnClickListener(this);        s_delete.setOnClickListener(this);        s_tv.setText(getIntent().getStringExtra(NotesDB.CONTENT));    }    @Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.s_delete:                deleteDate();                finish();                break;            case R.id.s_back:                finish();                break;        }    }    public void deleteDate() {        dbWriter.delete(NotesDB.TABLE_NAME,                "_id=" + getIntent().getIntExtra(NotesDB.ID, 0), null);    }}

AddContent.java

package com.example.admin_pc.adapter;import java.text.SimpleDateFormat;import java.util.Date;import android.app.Activity;import android.content.ContentValues;import android.database.sqlite.SQLiteDatabase;import android.os.Bundle;import android.view.View;import android.view.View.OnClickListener;import android.widget.Button;import android.widget.EditText;import android.widget.ImageView;import android.widget.VideoView;/** * Created by Admin-PC on 2015/3/2. * */public class AddContent extends Activity implements OnClickListener {    private String val;    private Button savebtn, deletebtn;    private EditText ettext;    private NotesDB notesDB;    private SQLiteDatabase dbWriter;    @Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.addcontent);        val = getIntent().getStringExtra("flag");        savebtn = (Button) findViewById(R.id.save);        deletebtn = (Button) findViewById(R.id.delete);        ettext = (EditText) findViewById(R.id.ettext);        savebtn.setOnClickListener(this);        deletebtn.setOnClickListener(this);        notesDB = new NotesDB(this);        dbWriter = notesDB.getWritableDatabase();    }    @Override    public void onClick(View v) {        switch (v.getId()) {            case R.id.save:                addDB();                finish();                break;            case R.id.delete:                finish();                break;        }    }    public void addDB() {        ContentValues cv = new ContentValues();        cv.put(NotesDB.CONTENT, ettext.getText().toString());        cv.put(NotesDB.TIME, getTime());        dbWriter.insert(NotesDB.TABLE_NAME, null, cv);    }    private String getTime() {        SimpleDateFormat format = new SimpleDateFormat("yyyy年MM月dd日 HH:mm:ss");        Date curDate = new Date();        String str = format.format(curDate);        return str;    }}

MyAdapter.java

package com.example.admin_pc.adapter;import android.content.Context;import android.database.Cursor;import android.view.LayoutInflater;import android.view.View;import android.view.ViewGroup;import android.widget.BaseAdapter;import android.widget.LinearLayout;import android.widget.TextView;/** * Created by Admin-PC on 2015/3/3. * */public class MyAdapter extends BaseAdapter {    private Context context;    private Cursor cursor;    private LinearLayout layout;    public MyAdapter(Context context, Cursor cursor) {        this.context = context;        this.cursor = cursor;    }    @Override    public int getCount() {        return cursor.getCount();    }    @Override    public Object getItem(int position) {        return cursor.getPosition();    }    @Override    public long getItemId(int position) {        // TODO Auto-generated method stub        return position;    }    public View getView(int position, View convertView, ViewGroup parent) {        LayoutInflater inflater = LayoutInflater.from(context);        layout = (LinearLayout) inflater.inflate(R.layout.cell, null);        TextView contenttv = (TextView) layout.findViewById(R.id.list_content);        TextView timetv = (TextView) layout.findViewById(R.id.list_time);        cursor.moveToPosition(position);        String content = cursor.getString(cursor.getColumnIndex("content"));        String time = cursor.getString(cursor.getColumnIndex("time"));        contenttv.setText(content);        timetv.setText(time);        return layout;    }}

NotesDB.java

package com.example.admin_pc.adapter;import android.content.Context;import android.database.sqlite.SQLiteDatabase;import android.database.sqlite.SQLiteOpenHelper;/** * Created by Admin-PC on 2015/3/2. * */public class NotesDB extends SQLiteOpenHelper {    public static final String TABLE_NAME = "notes";    public static final String CONTENT = "content";    public static final String ID = "_id";    public static final String TIME = "time";    public NotesDB(Context context) {        super(context, "notes", null, 1);    }    @Override    public void onCreate(SQLiteDatabase db) {        db.execSQL("CREATE TABLE " + TABLE_NAME + " (" + ID                + " INTEGER PRIMARY KEY AUTOINCREMENT," + CONTENT                + " TEXT NOT NULL,"+ TIME + " TEXT NOT NULL)");    }    @Override    public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {    }}