当我调用函数'测试'我的应用程序崩溃。任何想法为什么会发生?Android Studio应用程序崩溃,数据库插入
DB类
package com.example.paulcosma.app2;
import android.content.ContentValues;
import android.content.Context;
import android.database.sqlite.SQLiteDatabase;
import android.database.sqlite.SQLiteOpenHelper;
public class DB extends SQLiteOpenHelper{
public static final String
dbName = "foods.db",
tableName = "foods",
colId = "id",colName = "name",colCarbs = "carbs";
public DB(Context context) {
super(context, dbName, null, 1);
}
@Override
public void onCreate(SQLiteDatabase db) {
db.execSQL("create table " + dbName + "(" + colId + " INTEGER PRIMARY KEY AUTOINCREMENT," + colName + " TEXT," + colCarbs + " REAL)");
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion) {
db.execSQL("drop table if exists " + dbName);
onCreate(db);
}
public boolean addFood(String Name, float Carbs){
SQLiteDatabase db = this.getWritableDatabase();
ContentValues contentValues = new ContentValues();
contentValues.put(colName,Name);
contentValues.put(colCarbs,Carbs);
long result = db.insert(tableName,null,contentValues);
return result != -1; // -1 == not inserted
}
}
MainActivity
package com.example.paulcosma.app2;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.view.View;
import android.widget.TextView;
import android.widget.Toast;
public class MainActivity extends AppCompatActivity {
DB db;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
db = new DB(this);
}
public void test(View v){
boolean insertedSuccessfully = db.addFood("Milk",4); // crashes when called
if(insertedSuccessfully)
Toast.makeText(this,"inserted",Toast.LENGTH_LONG).show();
else Toast.makeText(this,"not inserted",Toast.LENGTH_LONG).show();
}
}
logcat的
01-20 19:59:47.888 9565-9565/com。示例。 paulcos ma.app2 E/InstantRun: 在APK中找不到切片;中止。 01-20 19:59:47.988 9565-9565/com.example.paulcosma.app2 E/dalvikvm:无法找到类 'android.graphics.drawable.RippleDrawable',从方法 引用android.support.v7.widget .AppCompatImageHelper.hasOverlappingRendering 01-20 19:59:48.005 9565-9565/com.example.paulcosma.app2 E/TextView: zhangcl:从应用程序获取字体资源失败。 01-20 19:59:48.013 9565-9565/com.example.paulcosma.app2 E/TextView:zhangcl: 从应用程序获取字体资源失败 - 2. 01-20 19:59:48.045 9565-9565/com.example.paulcosma.app2 E/TextView:zhangcl:从应用程序获取字体 资源失败。 01-20 20:00 00:02.211 9565-9565/com.example.paulcosma.app2 E/SQLiteLog:(10)无法执行 文件读取,得到:0,amt:100,last Errno:2 01-20 20 :00:02.244 9565-9565/com.example.paulcosma.app2 E/SQLiteLog:(1)未知数据库 食物01-20 20:00:02.263 9565-9565/com.example.paulcosma.app2 E/AndroidRuntime :致命异常:主要
过程:com.example.paulcosma.app2,PID:9565
java.lang.IllegalStateException:无法 Android的执行方法:的onClick
请不要发布的代码,XML,或logcat的输出屏幕截图。请以文字形式发布所有文字。您还需要包含来自崩溃的堆栈跟踪。 http://stackoverflow.com/questions/23353173/uncomfort-myapp-has-stopped-how-can-i-solve-this http://stackoverflow.com/questions/3988788/what-is-a-stack-trace -and-如何灿我使用的,它到调试我的应用程序,错误 –