android开发新闻系统进行新闻保存到SQLite数据库的布局代码
以下是一个简单的布局代码示例,用于在Android开发中保存新闻到SQLite数据库:
activity_main.xml(主活动布局):
<RelativeLayout 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:paddingLeft="16dp"
android:paddingTop="16dp"
android:paddingRight="16dp"
android:paddingBottom="16dp"
tools:context=".MainActivity">
<EditText
android:id="@+id/editTextTitle"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="请输入新闻标题" />
<EditText
android:id="@+id/editTextContent"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:layout_below="@id/editTextTitle"
android:layout_marginTop="16dp"
android:hint="请输入新闻内容" />
<Button
android:id="@+id/buttonSave"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_below="@id/editTextContent"
android:layout_centerHorizontal="true"
android:layout_marginTop="16dp"
android:text="保存" />
</RelativeLayout>
MainActivity.java(主活动代码):
import android.content.ContentValues;
import android.database.sqlite.SQLiteDatabase;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.Button;
import android.widget.EditText;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
private EditText editTextTitle;
private EditText editTextContent;
private Button buttonSave;
private NewsDatabaseHelper databaseHelper;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
editTextTitle = findViewById(R.id.editTextTitle);
editTextContent = findViewById(R.id.editTextContent);
buttonSave = findViewById(R.id.buttonSave);
databaseHelper = new NewsDatabaseHelper(this);
buttonSave.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
saveNews();
}
});
}
private void saveNews() {
String title = editTextTitle.getText().toString().trim();
String content = editTextContent.getText().toString().trim();
if (title.isEmpty() || content.isEmpty()) {
Toast.makeText(this, "请输入新闻标题和内容", Toast.LENGTH_SHORT).show();
return;
}
SQLiteDatabase db = databaseHelper.getWritableDatabase();
ContentValues values = new ContentValues();
values.put("title", title);
values.put("content", content);
long newRowId = db.insert("news", null, values);
if (newRowId != -1) {
Toast.makeText(this, "新闻保存成功", Toast.LENGTH_SHORT).show();
editTextTitle.setText("");
editTextContent.setText("");
} else {
Toast.makeText(this, "新闻保存失败", Toast.LENGTH_SHORT).show();
}
db.close();
}
}
NewsDatabaseHelper.java(数据库帮助类):
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class NewsDatabaseHelper extends SQLiteOpenHelper {
private static final String DATABASE_NAME = "news.db";
private static final int DATABASE_VERSION = 1;
public NewsDatabaseHelper(Context context) {
super(context, DATABASE_NAME, null, DATABASE_VERSION);
}
@Override
public void onCreate(SQLiteDatabase db) {
String createTableQuery = "CREATE TABLE news (_id INTEGER PRIMARY KEY AUTOINCREMENT, title TEXT, content TEXT)";
db.execSQL(createTableQuery);
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
String dropTableQuery = "DROP TABLE IF EXISTS news";
db.execSQL(dropTableQuery);
onCreate(db);
}
}
以上代码示例中,我们创建了一个包含标题和内容的新闻表(news)来保存新闻数据。在点击保存按钮时,会将输入的新闻标题和内容保存到数据库中。
原文地址: http://www.cveoy.top/t/topic/hB94 著作权归作者所有。请勿转载和采集!