Question

当我单击activity_main.xml中显示的按钮时，我无法启动我的活动（显示消息）。我已经尝试解决onClick中的问题，但仍然无法运行它。我能知道是什么问题吗？谢谢。

以下是代码：

MainActivity.java

Data is created to represent just `12` columns of the dataset mentioned by OP.

set.seed(1)
dataset <- data.frame(col1 = sample(1:10,10),
                      col2 = sample(1:10,10),
                      col3 = sample(1:10,10),
                      col4 = sample(1:10,10),
                      col5 = sample(11:20,10),
                      col6 = sample(11:20,10),
                      col7 = sample(11:20,10),
                      col8 = sample(11:20,10),
                      col9 = sample(21:30,10),
                      col10 = sample(21:30,10),
                      col11 = sample(21:30,10),
                      col12 = sample(21:30,10)
                      )


dataset
#    col1 col2 col3 col4 col5 col6 col7 col8 col9 col10 col11 col12
# 1     3    3   10    5   19   15   20   14   25    23    27    30
# 2     4    2    2    6   16   18   13   18   27    21    24    27
# 3     5    6    6    4   17   14   14   13   24    26    23    23
# 4     7   10    1    2   14   12   19   19   23    27    30    24
# 5     2    5    9   10   18   11   18   17   30    25    29    21
# 6     8    7    8    8   20   16   12   15   22    24    22    26
# 7     9    8    7    9   11   17   15   20   29    22    21    28
# 8     6    4    5    1   12   19   17   12   21    28    25    25
# 9    10    1    3    7   13   13   11   16   28    30    28    29
# 10    1    9    4    3   15   20   16   11   26    29    26    22

activity_main.xml

public class MainActivity extends AppCompatActivity{

    public Button but1;

    public void init(){
        but1= (Button)findViewById(R.id.button1);
        but1.setOnClickListener(new View.OnClickListener() {

        @Override
            public void onClick(View v) {

                Intent display = new Intent(MainActivity.this, DisplayMessage.class);

                startActivity(display);
            }
        });
    }

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);

        Spinner mySpinner = (Spinner) findViewById(R.id.spinner1);

        ArrayAdapter<String> myAdapter = new ArrayAdapter<String>(MainActivity.this,android.R.layout.simple_list_item_1, getResources().getStringArray(R.array.products));

        myAdapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
        mySpinner.setAdapter(myAdapter);

    }
}

Answer 1

似乎您从未从init()方法中调用onCreate()。因此，but1从未被初始化，OnClickListener从未被设置。

单击按钮后无法启动其他活动（android）

1 个答案: