如何通过 switch compact 将值 1 插入 sq-lite 中的列

Posted 2023-04-19

【中文标题】如何通过 switch compact 将值 1 插入 sq-lite 中的列

【英文标题】：How to insert value 1 into a column in sq-lite through switch compact

【发布时间】：2020-03-01 16:57:13

【问题描述】：

当我在 recyclerView 内的卡片视图中单击 switch compact 时，我想在 SQLite 列中插入值 1 ..但是当我单击 switchCompact 时出现 NullPointeException。 enter image description here 在此先感谢.. 我是 android 新手

orderListAdapter.java

    public void onBindViewHolder(@NonNull final orderListHolder holder, final int position) 
    final orderbook orderbook = orderbookList.get(position);
    holder.orderno.setText(orderbook.orderNo + " ");
    holder.customerName.setText(orderbook.customerName);
    holder.itemName.setText(orderbook.itemName);
    holder.workCompleteSwicth.setOnCheckedChangeListener(new CompoundButton.OnCheckedChangeListener() 
        @Override
        public void onCheckedChanged(CompoundButton compoundButton, boolean b) 
            if(holder.workCompleteSwicth.isChecked()) 
                myDb.InsertWorkComplete(1);
            


        
    );

DatabaseHelper.java

public void InsertWorkComplete( int isWorkComplete)

    SQLiteDatabase db=this.getWritableDatabase();
   ContentValues contentValues=new ContentValues();


 contentValues.put(COLUMN_ISWORKCOMPLETE,isWorkComplete);

     db.update(TABLE_NAME, contentValues, null, null);

logcat :-

Process: com.example.android.saffrondesigner, PID: 5359
    java.lang.NullPointerException
        at com.example.android.saffrondesigner.orderListAdapter$1.onCheckedChanged(orderListAdapter.java:60)
        at android.widget.CompoundButton.setChecked(CompoundButton.java:127)
        at androidx.appcompat.widget.SwitchCompat.setChecked(SwitchCompat.java:1060)
        at androidx.appcompat.widget.SwitchCompat.toggle(SwitchCompat.java:1055)
        at android.widget.CompoundButton.performClick(CompoundButton.java:99)
        at android.view.View$PerformClick.run(View.java:18797)
        at android.os.Handler.handleCallback(Handler.java:808)
        at android.os.Handler.dispatchMessage(Handler.java:103)
        at android.os.Looper.loop(Looper.java:193)
        at android.app.ActivityThread.main(ActivityThread.java:5299)
        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:829)
        at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:645)
        at dalvik.system.NativeStart.main(Native Method)

【参考方案1】：

在这里

public void onCheckedChanged(CompoundButton compoundButton, boolean b) 
            if(holder.workCompleteSwicth.isChecked()) 
                myDb.InsertWorkComplete(1);
            

我想只是改变holder.workCompleteSwicth.isChecked() 到

`public void onCheckedChanged(CompoundButton compoundButton, boolean b) 
                if(b) 
                    myDb.InsertWorkComplete(1);
                    //u can setChecked of switch her ex: model.setChecked(true);
                `

如果它不起作用，你可以在你的 logcat 中发布错误

【讨论】：

首先感谢您的回复，很抱歉您的建议不起作用。我将发布我的logcat，希望您能帮助我找到解决方案

【参考方案2】：

首先不要在适配器上做数据库相关的工作，我会为你提供解决方案，你可以在片段上的活动上做数据库相关的工作。 首先在您的适配器中创建一个接口，

interface WorkCompleteInteraction 
        void onWorkComplete(int position, OrderBook orderbook);
    

在构造函数中获取接口，

public class MyAdapter extends RecyclerView.Adapter<MyAdapter.MyViewHolder> 
    private WorkCompleteInteraction interaction;
    private Context mContext;

    public MyAdapter(WorkCompleteInteraction interaction, Context mContext) 
        this.interaction = interaction;
        this.mContext = mContext;
    

向您的活动/片段发送回调，

    @Override
    public void onBindViewHolder(@NonNull MyViewHolder holder, int position) 
        final orderbook orderbook = orderbookList.get(position);
        if (interaction != null) 
            interaction.onWorkComplete(position, orderbook);
        
    

在活动/片段中初始化您的适配器，

MyAdapter adapter = new MyAdapter(this,this);

在您的活动中实现您的界面，

public class TestActivity extends AppCompatActivity implements MyAdapter.WorkCompleteInteraction 

最后重写你的方法，

    @Override
    public void onWorkComplete(int position, OrderBook orderbook) 
        //do your database related work here