Android SQLite数据库

前言

以前写PHP的时候，内置了print_r()和var_dump()两个函数用于打印输出任意类型的数据内部结构，现在做Android的开发，发现并没有这种类似的函数，对于数据库的查看很不方便，于是就写了一下查看数据库表的方法代码。

代码实现

import java.util.Arrays;

import android.app.Activity;

import android.database.Cursor;

import android.database.sqlite.SQLiteDatabase;

import android.os.Bundle;

import android.util.Log;

import android.view.View;

import android.view.View.OnClickListener;

import android.widget.Button;

public class SecondActivity extends Activity {

public static final String TAG = "Debug Info";

@Override

protected void onCreate(Bundle savedInstanceState) {

super.onCreate(savedInstanceState);

((Button)findViewById(R.id.btnQue)).setOnClickListener(new OnClickListener() {

@Override

public void onClick(View v) {

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

SQLiteDatabase db = dbhelper.getWritableDatabase();

//核心区

//读取系统表 sqlite_master

String sql = "select * from sqlite_master";

Cursor cursor = db.rawQuery(sql, null);

//打印表的所有列名

Log.i(TAG, Arrays.toString(cursor.getColumnNames()));

//打印当前数据库中的所有表

if (cursor.moveToFirst()) {

do {

String str = "";

for (String item : cursor.getColumnNames()) {

str += item + ": " + cursor.getString(cursor.getColumnIndex(item)) + "\n";

}

Log.i(TAG, str);

} while (cursor.moveToNext());

}

}

});

}

}

功能扩展

查看表是否存在

public Boolean tableIsExist(SQLiteDatabase db, String tableName){

boolean result = false;

Cursor cursor = null;

if(tableName == null){

return result;

}

String sql = "select count(*) from sqlite_master where type ='table' and name ='"+tableName.trim()+"'";

cursor = db.rawQuery(sql, null);

if(cursor.moveToNext()){

if(cursor.getInt(0) > 0){

result = true;

}

}

return result;

}

查看数据库中有哪些表

public ArrayList tablesInDB(SQLiteDatabase db){

ArrayList list = new ArrayList();

String sql = "select name from sqlite_master where type='table'";

Cursor cursor = db.rawQuery(sql, null);

if (cursor.moveToFirst()) {

do {

list.add(cursor.getString(0));

} while (cursor.moveToNext());

}

return list;

}

感谢阅读，希望能帮助到大家，谢谢大家对本站的支持！