第二次插入数据时出现Android RoomDatabase异常

我正在使用RoomDatabase将数据上载到数据库。第一次上传数据成功，但第二次尝试上传另一个数据时出现异常，问题是contactDao.insert（contact）在MainActivity.class中。这是我第一次使用房间数据库。请解释一下这个问题

例外情况：

android.database.sqlite.SQLiteConstraintException: UNIQUE constraint failed: contact.index (code 1555)
    #################################################################
    Error Code : 1555 (SQLITE_CONSTRAINT_PRIMARYKEY)
    Caused By : Abort due to constraint violation.
        (UNIQUE constraint failed: contact.index (code 1555))
    #################################################################
        at android.database.sqlite.SQLiteConnection.nativeExecuteForLastInsertedRowId(Native Method)
        at android.database.sqlite.SQLiteConnection.executeForLastInsertedRowId(SQLiteConnection.java:857)
        at android.database.sqlite.SQLiteSession.executeForLastInsertedRowId(SQLiteSession.java:788)
        at android.database.sqlite.SQLiteStatement.executeInsert(SQLiteStatement.java:86)
        at android.arch.persistence.db.framework.FrameworkSQLiteStatement.executeInsert(FrameworkSQLiteStatement.java:50)
        at android.arch.persistence.room.EntityInsertionAdapter.insert(EntityInsertionAdapter.java:64)
        at com.globemaster.com.roomdatabase.ContactDao_Impl.insert(ContactDao_Impl.java:97)
        at com.globemaster.com.roomdatabase.MainActivity$1.onClick(MainActivity.java:34)
        at android.view.View.performClick(View.java:5716)
        at android.widget.TextView.performClick(TextView.java:10926)
        at android.view.View$PerformClick.run(View.java:22596)
        at android.os.Handler.handleCallback(Handler.java:739)
        at android.os.Handler.dispatchMessage(Handler.java:95)
        at android.os.Looper.loop(Looper.java:148)
        at android.app.ActivityThread.main(ActivityThread.java:7325)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1230)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:1120)

Contact.class：

import android.arch.persistence.room.ColumnInfo;
import android.arch.persistence.room.Entity;
import android.arch.persistence.room.PrimaryKey;
import android.support.annotation.NonNull;

@Entity(tableName = "contact")
public class Contact {
    public int getIndex() {
        return index;
    }

    public void setIndex(int index) {
        this.index = index;
    }

    @ColumnInfo(name = "index")
    @PrimaryKey(autoGenerate = true)
    private int index=1;

    @ColumnInfo(name = "phnmbr")
    @NonNull
    private String phoneNumber;

    @ColumnInfo(name = "firstnme")
    private String firstname;

    @ColumnInfo(name = "lastnme")
    String lastname;

    public String getFirstname() {
        return firstname;
    }

    public void setFirstname(String firstname) {
        this.firstname = firstname;
    }

    public String getLastname() {
        return lastname;
    }

    public void setLastname(String lastname) {
        this.lastname = lastname;
    }

    @NonNull
    public String getPhoneNumber() {
        return phoneNumber;
    }

    public void setPhoneNumber(@NonNull String phoneNumber) {
        this.phoneNumber = phoneNumber;
    }


    }

ContactDao（接口）：

MainActivity.java：

appdatabase= Room.databaseBuilder(MainActivity.this,AppDatabase.class,"db-contacts").allowMainThreadQueries().build();
contactDao=appdatabase.getContactDAO();
upload.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
         Contact contact=new Contact();
         contact.setFirstname(firstname.getText().toString());
         contact.setLastname(lastname.getText().toString());
         contact.setPhoneNumber(phonenumber.getText().toString());
         contactDao.insert(contact);
        Toast.makeText(getApplicationContext(),"Uploaded",Toast.LENGTH_SHORT).show();

    }
});

---

我不使用Room，但正如我所看到的，您有一个自动生成的主键，但您总是将其设置为1，从Contact类中删除

=1

，您的问题应该得到解决：）

例如：

@ColumnInfo(name = "index")
@PrimaryKey(autoGenerate = true)
private int index;

---

我不使用Room，但正如我所看到的，您有一个自动生成的主键，但您总是将其设置为1，从Contact类中删除

=1

，您的问题应该得到解决：）

例如：

@ColumnInfo(name = "index")
@PrimaryKey(autoGenerate = true)
private int index;

---

知道如何在房间中监听数据库操作（如插入、更新）吗？检查LiveData组件！它正是您所需要的：知道如何在房间中侦听诸如插入、更新之类的db操作吗？请检查LiveData组件！它正是您所需要的：

@ColumnInfo(name = "index")
@PrimaryKey(autoGenerate = true)
private int index;