java微调器值未从一个活动传递到另一个活动

Question

ViewToken。类别：

    spinnerGenre = (Spinner) findViewById(R.id.spinnerGenres);
    spinnerGenre1 = (Spinner) findViewById(R.id.spinner);

    docname = spinnerGenre1.getSelectedItem().toString();
    session = spinnerGenre.getSelectedItem().toString();

    next=(Button)findViewById(R.id.button4);
    next.setOnClickListener(new View.OnClickListener() {
        @Override
        public void onClick(View v) {
            Intent next=new Intent(ViewToken.this,Tokens.class);
            next.putExtra("docname", docname.toString());
            next.putExtra("session", session.toString());
            startActivity(next);
        }
    });

代币。阶级

    Intent i2 = getIntent();
    final String docname = i2.getStringExtra("docname");
    final String session = i2.getStringExtra("session");

ViewToken中的微调器值。类不会传递给令牌。阶级

Answer 1

对getSelectedItem()的调用应该在onClick侦听器中进行，以便它获得所选的最新值

因此onClick()方法将是：

@Override
public void onClick(View v) {
    docname = spinnerGenre1.getSelectedItem().toString();
    session = spinnerGenre.getSelectedItem().toString();
    Intent next=new Intent(ViewToken.this,Tokens.class);
    next.putExtra("docname", docname);
    next.putExtra("session", session);
    startActivity(next);
}

对getSelectedItem()的调用很可能是在选择任何内容之前进行的，因此，在意图中的值put()不正确

Answer 2

int positionOfSelectedDataFromSpinner;
iv.putExtra("position", positionOfSelectedDataFromSpinner);

创建一个新方法

spinner.setOnItemSelectedListener(new AdapterView.OnItemSelectedListener() {
            @Override
            public void onItemSelected(AdapterView<?> adapterView, View view, int i, long l) {
                positionOfSelectedDataFromSpinner= i;
            }

            @Override
            public void onNothingSelected(AdapterView<?> adapterView) {

            }
        });

在第二个活动中

int positionToShowToSpinner = iv.getIntExtra("position",0);
spinner.setSelection(positionToShowToSpinner);

Answer 3

在ViewToken中更改此选项。阶级

next.putExtra("docname", docname);
next.putExtra("session", session);

您可以在令牌中执行以下操作。阶级

Bundle extras = getIntent().getExtras();
String docname = extras.getString("docname");
String session = extras.getString("session");

Answer 4

在发送之前从微调器获取值

next.setOnClickListener(new View.OnClickListener() {
    @Override
    public void onClick(View v) {
        docname = spinnerGenre1.getSelectedItem().toString();
        session = spinnerGenre.getSelectedItem().toString();

        Intent next=new Intent(ViewToken.this,Tokens.class);
        next.putExtra("docname", docname.toString());
        next.putExtra("session", session.toString());
        startActivity(next);
    }
});