第一行代码 第7章 内容提供器 --实现跨程序数据共享

DatabaseTest.apk源码如下:

MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

private MyDatabaseHelper myDatabaseHelper;

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

myDatabaseHelper = new MyDatabaseHelper(this, "BookStore.db", null, 1);

Button createDatabase = (Button)findViewById(R.id.create_database);
createDatabase.setOnClickListener(this);

Button addData = (Button)findViewById(R.id.add_data);
addData.setOnClickListener(this);

Button updateData = (Button)findViewById(R.id.update_data);
updateData.setOnClickListener(this);

Button deleteData = (Button)findViewById(R.id.delete_data);
deleteData.setOnClickListener(this);

Button queryData = (Button)findViewById(R.id.query_data);
queryData.setOnClickListener(this);
}

@Override
public void onClick(View view) {
SQLiteDatabase db = myDatabaseHelper.getReadableDatabase();
ContentValues values = new ContentValues();
switch (view.getId()){
case R.id.create_database:
//myDatabaseHelper.getReadableDatabase();
break;
case R.id.add_data:
values.put("author", "admin");
values.put("book_name", "Android");
values.put("pages", 800);
values.put("price", 68.4);
db.insert("Book", null, values);
values.clear();

values.put("author", "sky");
values.put("book_name", "Iphone");
values.put("pages", 1000);
values.put("price", 78.2);
db.insert("Book", null, values);
break;
case R.id.update_data:
values.put("price", 12.02);
db.update("Book", values, "book_name=?", new String[]{"Android"});
break;
case R.id.delete_data:
db.delete("Book", "book_name=?", new String[]{"Android"});
break;
case R.id.query_data:
int count = 0;
Cursor cursor = db.query("Book", null, null, null, null, null,null);
if(cursor.moveToFirst()){
do{
String author = cursor.getString(cursor.getColumnIndex("author"));
Toast.makeText(this,author+":"+count,Toast.LENGTH_SHORT).show();
count++;
}while (cursor.moveToNext());
}
cursor.close();
break;
default:
break;
}

}
}

MyDatabaseHelper.java

public class MyDatabaseHelper extends SQLiteOpenHelper {

private Context context;
public static final String CREATE_BOOK = "create table Book (" +
"id integer primary key autoincrement," +
"author text," +
"price real," +
"pages integer," +
"book_name text)";

public static final String CREATE_CATEGORY = "create table Category (" +
"id integer primary key autoincrement, " +
"category_name text, " +
"category_code integer)" ;

public MyDatabaseHelper(Context context, String name, SQLiteDatabase.CursorFactory factory, int version) {
super(context, name, factory, version);
this.context = context;
}

@Override
public void onCreate(SQLiteDatabase sqLiteDatabase) {
sqLiteDatabase.execSQL(CREATE_BOOK);
}

@Override
public void onUpgrade(SQLiteDatabase sqLiteDatabase, int i, int i1) {
sqLiteDatabase.execSQL(CREATE_CATEGORY);
}
}

MyContentProvider.java

public class MyContentProvider extends ContentProvider {

public static final int BOOK_DIR = 0;
public static final int BOOK_ITEM = 1;
public static final int CATEGORY_DIR = 2;
public static final int CATEGORY_ITEM = 3;

public static final String AUTHORITY = "com.sky.databasetest.provider";
private static UriMatcher uriMatcher;
private MyDatabaseHelper dbHelper;

static {
uriMatcher = new UriMatcher(UriMatcher.NO_MATCH);
uriMatcher.addURI(AUTHORITY, "Book", BOOK_DIR);
uriMatcher.addURI(AUTHORITY, "Book/#", BOOK_ITEM);
uriMatcher.addURI(AUTHORITY, "Category", CATEGORY_DIR);
uriMatcher.addURI(AUTHORITY, "Category/#", CATEGORY_ITEM);

}
public MyContentProvider() {
}

@Override
public boolean onCreate() {
dbHelper = new MyDatabaseHelper(getContext(), "BookStore.db", null, 2);
return true;
}

@Override
public String getType(Uri uri) {
String type = null;
switch (uriMatcher.match(uri)){
case BOOK_DIR:
type = "vnd.android.cursor.dir/vnd.com.sky.databasetest.provider.Book";
break;
case BOOK_ITEM:
type = "vnd.android.cursor.item/vnd.com.sky.databasetest.provider.Book";
break;
case CATEGORY_DIR:
type = "vnd.android.cursor.dir/vnd.com.sky.databasetest.provider.Category";
break;
case CATEGORY_ITEM:
type = "vnd.android.cursor.item/vnd.com.sky.databasetest.provider.Category";
break;
default:
break;
}
return type;
}

@Override
public Uri insert(Uri uri, ContentValues values) {

SQLiteDatabase db = dbHelper.getReadableDatabase();
Uri uriRet=null;
switch (uriMatcher.match(uri)){
case BOOK_DIR:
case BOOK_ITEM:
long newBookId = db.insert("Book", null, values);
uriRet = Uri.parse("content://" + AUTHORITY + "/Book/"+newBookId);
break;
case CATEGORY_DIR:
case CATEGORY_ITEM:
long newCategoryId = db.insert("Category", null, values);
uriRet = Uri.parse("content://" + AUTHORITY + "/Category/"+newCategoryId);
break;
default:break;
}
return uriRet;
}

@Override
public Cursor query(Uri uri, String[] projection, String selection,
String[] selectionArgs, String sortOrder) {

SQLiteDatabase db = dbHelper.getReadableDatabase();
Cursor cursor = null;
switch (uriMatcher.match(uri)){
case BOOK_DIR:
cursor = db.query("Book", projection, selection, selectionArgs, null, null, sortOrder);
break;
case BOOK_ITEM:
String bookId = uri.getPathSegments().get(1);
cursor = db.query("Book", projection, "id=?", new String[]{bookId}, null, null, sortOrder);
break;
case CATEGORY_DIR:
cursor = db.query("Category", projection, selection, selectionArgs, null, null, sortOrder);
break;
case CATEGORY_ITEM:
String categoryId = uri.getPathSegments().get(1);
cursor = db.query("Category", projection, "id=?", new String[]{categoryId}, null, null, sortOrder);
break;
default:break;
}
return cursor;
}

@Override
public int update(Uri uri, ContentValues values, String selection,
String[] selectionArgs) {

SQLiteDatabase db = dbHelper.getReadableDatabase();
int updateRows = 0;
switch (uriMatcher.match(uri)){
case BOOK_DIR:
updateRows = db.update("Book", values, selection, selectionArgs);
break;
case BOOK_ITEM:
String bookId = uri.getPathSegments().get(1);
updateRows = db.update("Book", values, "id=?", new String[]{bookId});
break;
case CATEGORY_DIR:
updateRows = db.update("Category", values, selection, selectionArgs);
break;
case CATEGORY_ITEM:
String categoryId = uri.getPathSegments().get(1);
updateRows = db.update("Category", values, "id=?", new String[]{categoryId});
break;
default:break;
}
return updateRows;
}

@Override
public int delete(Uri uri, String selection, String[] selectionArgs) {

SQLiteDatabase db = dbHelper.getReadableDatabase();
int deleteRows = 0;
switch (uriMatcher.match(uri)){
case BOOK_DIR:
deleteRows = db.delete("Book", selection, selectionArgs);
break;
case BOOK_ITEM:
String bookId = uri.getPathSegments().get(1);
deleteRows = db.delete("Book", "id=?", new String[]{bookId});
break;
case CATEGORY_DIR:
deleteRows = db.delete("Category", selection, selectionArgs);
break;
case CATEGORY_ITEM:
String categoryId = uri.getPathSegments().get(1);
deleteRows = db.delete("Category", "id=?", new String[]{categoryId});
break;
default:break;
}
return deleteRows;
}

}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.sky.databasetest">

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>

<provider
android:name=".MyContentProvider"
android:authorities="com.sky.databasetest.provider"
android:enabled="true"
android:exported="true">

</provider>
</application>

</manifest>

ProviderTest.apk源码如下：

MainActivity.java

public class MainActivity extends AppCompatActivity implements View.OnClickListener {

public static final String AUTHORITY = "com.sky.databasetest.provider";
private String newId;

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

Button btnAddData = (Button)findViewById(R.id.btnAddData);
Button btnQueryData = (Button)findViewById(R.id.btnQueryData);
Button btnUpdateData = (Button)findViewById(R.id.btnUpdateData);
Button btnDeleteData = (Button)findViewById(R.id.btnDeleteData);

btnAddData.setOnClickListener(this);
btnQueryData.setOnClickListener(this);
btnUpdateData.setOnClickListener(this);
btnDeleteData.setOnClickListener(this);
}

@Override
public void onClick(View view) {
switch (view.getId()){
case R.id.btnAddData: {
Uri uri = Uri.parse("content://"+ AUTHORITY + "/Book");
ContentValues values = new ContentValues();
values.put("book_name", "adfsaffsf");
values.put("author", "aha");
values.put("price", "45.3");
values.put("pages", "120");
Uri newUri = getContentResolver().insert(uri, values);
newId = newUri.getPathSegments().get(1);
}
break;
case R.id.btnQueryData: {
Uri uri = Uri.parse("content://"+ AUTHORITY+"/Book");
Cursor cursor = getContentResolver().query(uri, null, null, null, null);
if(cursor!=null){
while (cursor.moveToNext()){
String name = cursor.getString(cursor.getColumnIndex("book_name"));
String author = cursor.getString(cursor.getColumnIndex("author"));
int page = cursor.getInt(cursor.getColumnIndex("pages"));
double price = cursor.getDouble(cursor.getColumnIndex("price"));
Log.d("MainActivity", "book name is :" + name);
Log.d("MainActivity", "book author is :" + author);
Log.d("MainActivity", "book page is :" + page);
Log.d("MainActivity", "book price is :" + price);
}
cursor.close();
}
}
break;
case R.id.btnUpdateData:{
Uri uri = Uri.parse("content://"+ AUTHORITY + "/Book/" + newId);
ContentValues values = new ContentValues();
values.put("price", "22.6");
getContentResolver().update(uri, values, null, null);
}
break;
case R.id.btnDeleteData:{
Uri uri = Uri.parse("content://"+ AUTHORITY + "/Book/" + newId);
getContentResolver().delete(uri, null, null);
}
break;
default:
break;
}
}
}

AndroidManifest.xml

<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.sky.providertest">

<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:supportsRtl="true"
android:theme="@style/AppTheme">
<activity android:name=".MainActivity">
<intent-filter>
<action android:name="android.intent.action.MAIN" />

<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>

</manifest>