Android：带有蓝牙和图形绘制的选项卡式活动，如何？

Question

I am very new to Android, but I would like to develop my own app for a future project. The basic idea of this is to have 2 tabs (for now).

The first tab, Bluetooth, will have a button to establish a connection between Android and a bluetooth module.

The second tab, Graph, needs to read the input stream and take this data to plot a graph against time.

Now my question is:

Where exactly do I need to do what?

1. MainActivity handles the creation of the tabs
2. BluetoothTab inflates the layout of bluetooth_tab.xml
3. Graph inflates the layout of graph_tab.xml

My problem right now is that I don't know where to put the bluetooth connection stuff. Do I put it in the MainActivity?

If I do place the bluetooth connection stuff in the MainActivity, how can I make use of it from within the BluetoothTab fragment?

Could someone point me in the right direction with maybe an example of how this is usually done?

Here some code:

MainActivity

package com.bavilo.braumeister;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.support.v4.view.ViewPager;
import android.support.v7.app.ActionBarActivity;
import android.os.Bundle;
import android.support.v7.widget.Toolbar;
import android.view.Menu;
import android.view.MenuItem;
import android.widget.Button;
import android.view.View;
import android.view.View.OnClickListener;
import android.widget.Toast;

public class MainActivity extends ActionBarActivity {

    /* Declaring Your View and Variables */

    Toolbar toolbar;
    ViewPager pager;
    ViewPagerAdapter adapter;
    SlidingTabLayout tabs;
    CharSequence Titles[] = {"Bluetooth","Graph"};
    int Numboftabs = 2;

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

        // Creating The Toolbar and setting it as the Toolbar for the activity
        toolbar = (Toolbar) findViewById(R.id.tool_bar);
        setSupportActionBar(toolbar);

        // Creating The ViewPagerAdapter and Passing Fragment Manager, Titles fot the Tabs and Number Of Tabs.
        adapter =  new ViewPagerAdapter(getSupportFragmentManager(),Titles,Numboftabs);

        // Assigning ViewPager View and setting the adapter
        pager = (ViewPager) findViewById(R.id.pager);
        pager.setAdapter(adapter);

        // Assiging the Sliding Tab Layout View
        tabs = (SlidingTabLayout) findViewById(R.id.tabs);
        tabs.setDistributeEvenly(true); // To make the Tabs Fixed set this true, This makes the tabs Space Evenly in Available width

        // Setting Custom Color for the Scroll bar indicator of the Tab View
        tabs.setCustomTabColorizer(new SlidingTabLayout.TabColorizer() {
            @Override
            public int getIndicatorColor(int position) {
                return getResources().getColor(R.color.tabsScrollColor);
            }
        });

        // Setting the ViewPager For the SlidingTabsLayout
        tabs.setViewPager(pager);
    }

    @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
        switch(id) {
            case R.id.menu_info:

                new AlertDialog.Builder(this).setTitle("About").setMessage("Hello").show();
                break;
        }

        return super.onOptionsItemSelected(item);
    }
}

BluetoothTab

package com.bavilo.braumeister;

import android.bluetooth.BluetoothAdapter;
import android.bluetooth.BluetoothDevice;
import android.bluetooth.BluetoothSocket;
import android.content.BroadcastReceiver;
import android.content.Context;
import android.content.Intent;
import android.content.IntentFilter;
import android.os.Bundle;
import android.os.Handler;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.TextView;
import android.widget.Toast;

import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.UUID;

public class BluetoothTab extends Fragment {

    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.bluetooth_tab,container,false);
        text = (TextView) v.findViewById(R.id.text);
        return v;
    }
}

Graph

package com.bavilo.braumeister;

import android.os.Bundle;
import android.support.annotation.Nullable;
import android.support.v4.app.Fragment;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;

public class Tab2 extends Fragment {

    @Override
    public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
        View v = inflater.inflate(R.layout.tab_2,container,false);
        return v;
    }
}

Answer 1

All BT connection associated logic should definitely go into MainActivity because both tabs are going to use it. The best way to do it is to define a callback interface that MainActivity will implement, which will allow the Fragments to access the BT related functionality.

Keep the logic in Fragments to minimum. For example: the first Fragment will just register OnClickListener with the button, and call one of the callback methods of MainActivity (this method will initiate BT connection).

The steps involved are very similar to ones explained here: http://developer.android.com/training/basics/fragments/communicating.html