Question

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_customer);
    Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
    setSupportActionBar(toolbar);
    ds = new DataSource(getApplicationContext());

    FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
    fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            myDialog = new Dialog(view.getContext());
            myDialog.setContentView(R.layout.popup_add_customers);

            btnSave = (Button)findViewById(R.id.btnSave);
            btnSave.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(v.getContext(), "savebutton", Toast.LENGTH_LONG).show();
                }
            });

            myDialog.show();
        }
    });
}

现在我只想在“保存”按钮上举杯。

它给我下面的错误

Attempt to invoke virtual method 'void android.widget.Button.setOnClickListener(android.view.View$OnClickListener)' on a null object reference

提前感谢，真的需要帮助...

Answer 1

您的问题出在btnSave findViewById

像这样改变

fab.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View view) {
            myDialog = new Dialog(view.getContext());
            myDialog.setContentView(R.layout.popup_add_customers);

            btnSave = (Button)myDialog.findViewById(R.id.btnSave);
            btnSave.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    Toast.makeText(v.getContext(), "savebutton", Toast.LENGTH_LONG).show();
                }
            });

            myDialog.show();
        }
    });

Answer 2

您正在尝试将findViewById插入对话框中的btnSave。您需要在对话框上调用findViewById：

btnSave = (Button)myDialog.findViewById(R.id.btnSave);

Answer 3

请勿放置

btnSave = (Button)findViewById(R.id.btnSave);
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(v.getContext(), "savebutton", Toast.LENGTH_LONG).show();
            }
        });

在OnClick方法中，您需要将其放在OnCreate方法中

尝试一下：

    protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_customer);
Toolbar toolbar = (Toolbar) findViewById(R.id.toolbar);
setSupportActionBar(toolbar);
ds = new DataSource(getApplicationContext());
 btnSave = (Button)findViewById(R.id.btnSave);
        btnSave.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                Toast.makeText(v.getContext(), "savebutton", Toast.LENGTH_LONG).show();
            }
        });
  FloatingActionButton fab = (FloatingActionButton) findViewById(R.id.fab);
   fab.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View view) {
        myDialog = new Dialog(view.getContext());
        myDialog.setContentView(R.layout.popup_add_customers);



        myDialog.show();
    }
});
}

Fab Button的Onclick我有一个表格，我必须将其保存在SQL中

3 个答案: