如何通过Switch Compact将值1插入sq-lite中的列

2024-05-03 • 问答

当我在recyclerView ..内的卡片视图中单击开关契约时，我想在SQLite列中插入值1，但是当我单击switchCompact时，得到NullPointeException。 enter image description here 预先感谢..我是Android的新手

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)

在这里

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

我认为只需更改holder.workCompleteSwicth.isChecked()

`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，您可以在日志中发布错误

首先不要在适配器上进行数据库相关的工作，我将为您提供可以在Fragment上进行数据库相关的工作的说明。首先在您的适配器中创建一个接口，

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

在您的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;
    }

发送回调到您的活动/片段

    @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/片段中初始化适配器，

MyAdapter adapter = new MyAdapter(this,this);

在您的活动中添加界面，

public class TestActivity extends AppCompatActivity implements MyAdapter.WorkCompleteInteraction {

最后覆盖您的方法，

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

如何通过Switch Compact将值1插入sq-lite中的列

ms11042116 回答：如何通过Switch Compact将值1插入sq-lite中的列

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