我正在使用 Android Studio 和 Genymotion 作为模拟器创建一个应用程序,其中我在 3 个 EditText 中输入数据,当我单击按钮将其存储在 sqlite 数据库中时,它不起作用......这就是什么我在 LOGCAT 中看到
FATAL EXCEPTION: main
Process: com.example.aadeshmishra.com.sdk18, PID: 1551
java.lang.IllegalStateException: Could not execute method for android:onClick
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:293)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.reflect.InvocationTargetException
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
Caused by: java.lang.NullPointerException
at com.example.aadeshmishra.com.sdk18.ThirdActitvity.addData(ThirdActitvity.java:64)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at android.support.v7.app.AppCompatViewInflater$DeclaredOnClickListener.onClick(AppCompatViewInflater.java:288)
at android.view.View.performClick(View.java:4438)
at android.view.View$PerformClick.run(View.java:18422)
at android.os.Handler.handleCallback(Handler.java:733)
at android.os.Handler.dispatchMessage(Handler.java:95)
at android.os.Looper.loop(Looper.java:136)
at android.app.ActivityThread.main(ActivityThread.java:5001)
at java.lang.reflect.Method.invokeNative(Native Method)
at java.lang.reflect.Method.invoke(Method.java:515)
at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:785)
at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:601)
at dalvik.system.NativeStart.main(Native Method)
该按钮将调用 ThirdActivity 中名为 addData() 的方法。
here the code for ThirdActivity.java
public class ThirdActitvity extends AppCompatActivity {
EditText ed1,ed2,ed3;
Button B1;
UserDBHelper mydb;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_third);
ed1 = (EditText)findViewById(R.id.E1);
ed2 = (EditText)findViewById(R.id.E2);
ed3 = (EditText)findViewById(R.id.E3);
B1 = (Button) findViewById(R.id.addB);
}
public void addData(View view)
{
String name = ed1.getText().toString();
String desc = ed2.getText().toString();
String contact = ed3.getText().toString();
Boolean r1 = mydb.insertDataClient(name,desc,contact);
if(r1 == true)
{
Toast.makeText(this,"Data inserted",Toast.LENGTH_LONG).show();
}
else
{
Toast.makeText(this,"Data not inserted",Toast.LENGTH_LONG).show();
}
}
}
Here the Code for activity_third.xml
<EditText
android:id="@+id/E1"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/client"
android:textSize="20sp"
android:layout_marginEnd="20dp"/>
<EditText
android:id="@+id/E2"
android:layout_width="match_parent"
android:layout_height="wrap_content"
android:hint="@string/destail"
android:textSize="20sp"
android:layout_alignEnd="@+id/E1" />
<EditText
android:id="@+id/E3"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:inputType="text"
android:hint="@string/EN"
android:textSize="20sp"
android:layout_marginBottom="18dp"
android:layout_above="@+id/addB"
/>
<Button
android:id="@+id/addB"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:layout_marginBottom="49dp"
android:text="@string/add"
android:textSize="20sp"
android:layout_alignParentBottom="true"
android:layout_centerHorizontal="true"
android:onClick="addData"
/>
And at Last the UserDbHelper.java
public class UserDBHelper extends SQLiteOpenHelper {
// Database Details
private static final int DB_VER = 1;
private static final String DB_NAME = "DIARY_DB";
// Table Name
private static final String table_clientinfo = "Client_Info";
// columns
private static final String name = "Name";
private static final String desc = "Desc";
private static final String cont = "Contact";
// Create table -- ClientInfo
private String Create_ClientInfo = "Create table "+ table_clientinfo +"(" + id + " INTEGER PRIMARY KEY AUTOINCREMENT,"
+ name + " TEXT ," + desc + " TEXT,"
+ cont + " INTEGER)";
public UserDBHelper(Context context)
{
super(context,DB_NAME,null,DB_VER);
}
@Override
public void onCreate(SQLiteDatabase db)
{
db.execSQL(Create_ClientInfo);
db.close();
}
@Override
public void onUpgrade(SQLiteDatabase db, int oldVersion, int newVersion)
{
}
public Boolean insertDataClient(String Name, String Desc, String Contact)
{
SQLiteDatabase db = this.getWritableDatabase();
ContentValues con = new ContentValues();
con.put(name,Name);
con.put(desc,Desc);
con.put(cont,Contact);
long r = db.insert(table_clientinfo,null,con);
db.close();
if(r == -1)
{
return false;
}
else
{
return true;
}
}}
谁能告诉我出了什么问题..? 提前致谢..!
最佳答案
您需要在onCreate
中初始化mydb
(或者在任何地方使用它之前,尽管oncreate只执行一次,所以最好在onCreate
中进行)作为
UserDBHelper mydb;
@Override
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_third);
mydb = new UserDBHelper(this);
//^^^^^^^^^^^^^^^^^^^^^
ed1 = (EditText)findViewById(R.id.E1);
ed2 = (EditText)findViewById(R.id.E2);
ed3 = (EditText)findViewById(R.id.E3);
B1 = (Button) findViewById(R.id.addB);
}
关于java - 单击按钮且应用程序停止时出现 IllegalStateException,我们在Stack Overflow上找到一个类似的问题: https://stackoverflow.com/questions/47815251/