在Android中使用片段进行前向导航

时间:2015-02-24 12:30:39

标签: android android-fragments

我想知道是否有人知道使用Fragments实现前向和后向导航的方法?

我想从单个片段开始,当我按下下一个按钮时必须创建一个新的片段,当我按下后退按钮时,必须显示前一个片段。我的代码执行此操作并保存我对之前任何片段所做的任何更改,因为它们保存在后台堆栈中,但是,我希望前向导航也是如此,有什么方法可以实现这一点吗? / p>

更确切地说,我想创建10个片段,只需一个文本框,我可以在其中输入一些数据,每次输入数据并按下一个按钮,它必须导航到下一个片段,一个空文本框并保存先前的片段加上输入到后栈的数据(目前这样做)。因此,当我到达片段10时,我希望能够返回到片段1然后返回到片段10但是当我再次向前导航时,我最初输入的数据仍然必须存在。然后,当我导航到片段11时,它必须是一个空文本框。所以它必须是各种各样的前后导航系统。

下面的代码从代码动态生成片段,并动态添加视图(在运行时)。这是我目前为后退工作的代码。

    public class MainActivity extends Activity
{
    int mStackLevel = 0;

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

        Button IntegratedBiometricsButton = (Button) findViewById(R.id.integrated_biometrics_button);
        IntegratedBiometricsButton.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                Intent IBIntent = new Intent(MainActivity.this, SimpleScanActivity.class);
                startActivity(IBIntent);
            }
        });

        // Watch for button clicks.
        Button button = (Button) findViewById(R.id.new_fragment);
        button.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                addFragmentToStack();
            }
        });
        button = (Button) findViewById(R.id.delete_fragment);
        button.setOnClickListener(new View.OnClickListener()
        {
            public void onClick(View v)
            {
                getFragmentManager().popBackStack();
                if(mStackLevel > 0){mStackLevel--;}
            }
        });

        if (savedInstanceState == null)
        {
            // Do first time initialization -- add initial fragment.
            Fragment newFragment = CountingFragment.newInstance(mStackLevel);
            FragmentTransaction ft = getFragmentManager().beginTransaction();
            ft.add(R.id.simple_fragment, newFragment).commit();
        } else
        {
            mStackLevel = savedInstanceState.getInt("level");
        }
    }

    @Override
    public void onSaveInstanceState(Bundle outState)
    {
        super.onSaveInstanceState(outState);
        outState.putInt("level", mStackLevel);
    }

    @Override
    public boolean onCreateOptionsMenu(Menu menu)
    {
        // Inflate the menu; this adds items to the action bar if it is present.
        getMenuInflater().inflate(R.menu.menu_main, menu);
        return true;
    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item)
    {
        // Handle action bar item clicks here. The action bar will
        // automatically handle clicks on the Home/Up button, so long
        // as you specify a parent activity in AndroidManifest.xml.
        int id = item.getItemId();

        //noinspection SimplifiableIfStatement
        if (id == R.id.action_settings)
        {
            return true;
        }

        return super.onOptionsItemSelected(item);
    }

    void addFragmentToStack()
    {
        mStackLevel++;

        // Instantiate a new fragment.
        Fragment newFragment = CountingFragment.newInstance(mStackLevel);

        // Add the fragment to the activity, pushing this transaction
        // on to the back stack.
        FragmentTransaction ft = getFragmentManager().beginTransaction();
        ft.replace(R.id.simple_fragment, newFragment);
        ft.setTransition(FragmentTransaction.TRANSIT_FRAGMENT_OPEN);
        ft.addToBackStack(null);
        ft.commit();

    }

    public static class CountingFragment extends Fragment
    {
        int mNum;

        /**
         * Create a new instance of CountingFragment, providing "num"
         * as an argument.
         */
        static CountingFragment newInstance(int num)
        {
            CountingFragment f = new CountingFragment();

            // Supply num input as an argument.
            Bundle args = new Bundle();
            args.putInt("num", num);
            f.setArguments(args);

            return f;
        }

        /**
         * When creating, retrieve this instance's number from its arguments.
         */
        @Override
        public void onCreate(Bundle savedInstanceState)
        {
            super.onCreate(savedInstanceState);
            mNum = getArguments() != null ? getArguments().getInt("num") : 1;
        }

        /**
         * The Fragment's UI is just a simple text view showing its
         * instance number.
         */
        @Override
        public View onCreateView(LayoutInflater inflater, ViewGroup container, Bundle savedInstanceState)
        {
            int ID = 0;
            View v = inflater.inflate(R.layout.fragment_layout, container, false);

            LinearLayout fragmentLayout = (LinearLayout) v.findViewById(R.id.infoLayout);
            LinearLayout.LayoutParams lp = new LinearLayout.LayoutParams(LinearLayout.LayoutParams.FILL_PARENT, LinearLayout.LayoutParams.WRAP_CONTENT);

            TextView tv = new TextView(container.getContext());
            tv.setId(ID);
            ID++;
            tv.setTextSize(16);
            tv.setText("Fragment #" + mNum);
            tv.setGravity(Gravity.CENTER);
            tv.setLayoutParams(lp);
            fragmentLayout.addView(tv);

            EditText et = new EditText(container.getContext());
            et.setId(ID);
            ID++;
            et.setHint("Text");
            et.setGravity(Gravity.CENTER);
            et.setInputType(InputType.TYPE_CLASS_NUMBER);
            et.setLayoutParams(lp);
            fragmentLayout.addView(et);

            CheckBox cb = new CheckBox(container.getContext());
            cb.setId(ID);
            cb.setChecked(false);
            cb.setGravity(Gravity.LEFT);
            cb.setLayoutParams(lp);
            fragmentLayout.addView(cb);

            cb.setOnClickListener(new View.OnClickListener()
            {
                @Override
                public void onClick(View v)
                {
                    if(((CheckBox) v).isChecked())
                    {
                        Toast.makeText(v.getContext(), "Yo", Toast.LENGTH_LONG).show();
                    }
                }
            });
            ID++;

            ImageView iv = new ImageView(container.getContext());
            iv.setId(ID);
            iv.setImageResource(R.drawable.output);
            iv.setLayoutParams(lp);
            fragmentLayout.addView(iv);

            iv.setOnLongClickListener(new View.OnLongClickListener()
            {
                public boolean onLongClick(View v)
                {
                    Toast.makeText(v.getContext(), "It works", Toast.LENGTH_LONG).show();
                    return true;
                }
            });
            ID++;

            //View tv = v.findViewById(R.id.text);
            //((TextView) tv).setText("Fragment #" + mNum);
            //tv.setBackgroundDrawable(getResources().getDrawable(android.R.drawable.gallery_thumb));
            return v;
        }
    }
}

0 个答案:

没有答案