Question

大家好，我的代码有问题，我想要做的是当你改变微调器位置改变要显示的片段时，这就是我写的，但如果有人可以，它就不起作用请给我一个更好的方法，或者一个解决方案，这将是伟大的！

这是我的班级：

public class MainActivity extends ActionBarActivity {

private static final int NUM_PAGES = 2;

private ViewPager mPager;
private PagerAdapter mPagerAdapter;
String[] ciudades = { "Desde Paraná", "Desde Santa Fe", "Desde el pozo", "Desde abogacia"};
public int ciudad = 0;

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

    mPager = (ViewPager) findViewById(R.id.pager);

    Spinner sp = (Spinner) findViewById(R.id.spinner1);
    ArrayAdapter adapter = ArrayAdapter.createFromResource( this, R.array.opciones, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    sp.setAdapter(adapter);

    sp.setOnItemSelectedListener(new OnItemSelectedListener() {

        public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {

                ciudad = position;
                Toast.makeText(parentView.getContext(), ciudades[position], Toast.LENGTH_SHORT).show();         
        }

        public void onNothingSelected(AdapterView<?> parentView) {

        }
    });

    mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());
    mPager.setAdapter(mPagerAdapter);

}

@Override
public void onBackPressed() {
    if (mPager.getCurrentItem() == 0) {
        super.onBackPressed();
    } else {
        // Otherwise, select the previous step.
        mPager.setCurrentItem(mPager.getCurrentItem() - 1);
    }
}


private class ScreenSlidePagerAdapter extends FragmentStatePagerAdapter {
    public ScreenSlidePagerAdapter(FragmentManager fm) {
        super(fm);
    }

    @Override
    public Fragment getItem(int position) {

    /* Here is what I do, I took the value of ciudad and use it to display different group of fragment */
        if(ciudad == 0){
            switch(position){
                case 0:
                    return new Home_fragment();
                case 1:
                    return new Next_fragment();                 
            }
        }else if(ciudad == 1){
            switch(position){
                case 0:
                    return new Home_fragment_staFe();
                case 1:
                    return new Next_fragment_staFe();                   
            }
        }

        return null;
    }

    @Override
    public int getCount() {
        return NUM_PAGES;
    }
}
}

提前致谢！

修改

我已经尝试过kcoppock告诉我使用

的内容

notifyDataSetChanged（）

我这样使用，但它仍然无法正常工作

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

    mPager = (ViewPager) findViewById(R.id.pager);
    mPagerAdapter = new ScreenSlidePagerAdapter(getSupportFragmentManager());



    Spinner sp = (Spinner) findViewById(R.id.spinner1);
    ArrayAdapter adapter = ArrayAdapter.createFromResource( this, R.array.opciones, android.R.layout.simple_spinner_item);
    adapter.setDropDownViewResource(android.R.layout.simple_spinner_dropdown_item);
    sp.setAdapter(adapter);

    sp.setOnItemSelectedListener(new OnItemSelectedListener() {

        public void onItemSelected(AdapterView<?> parentView, View selectedItemView, int position, long id) {

                ciudad = position;
                Toast.makeText(parentView.getContext(), ciudades[position], Toast.LENGTH_SHORT).show();
                mPagerAdapter.notifyDataSetChanged();
        }

        public void onNothingSelected(AdapterView<?> parentView) {

        }
    });

    // Instantiate a ViewPager and a PagerAdapter.
    mPager.setAdapter(mPagerAdapter);

}

Answer 1

它永远不会再次调用getItem（），因为它不知道ciudad的值已经改变。在您的微调器值更改方法中，当您更改ciudad的值时，请调用mPagerAdapter.notifyDataSetChanged()以通知适配器它应该重新创建碎片。

此外，Home_fragment是Java非常规的命名模式。它应该是HomeFragment。

根据int值更改片段

1 个答案: