Android・iOS アプリ作成入門 Android 編

"OESPJEɾJ04 ΞϓϦ࡞੒ೖ໳ ,.$OPOZMFOF

͜ͷεϥΠυʹ͍ͭͯ w य़߹॓ͷ຅εϥΠυ w य़߹॓Ͱ͸J04ฤͷΈΛൃදʢͪ͜Βʣ w ͜͜ʹ͸"OESPJEฤΛऩ࿥ w J04ฤͱҰ෦ॏෳ͍ͯ͠·͢

ࣗݾ঺հ w OPOZMFOF ͷʹΕΜ w ,.$ೋճੜSPPU w (JU)VCIBUFOBFUDʜ w
QZUIPO KBWB "OESPJE   ,PUMJOFUDʜ

࿩͢͜ͱ

"OESPJEͱJ04ͷجຊ

"OESPJEͱJ04  Ͱ ಉػೳͷΞϓϦΛ࡞੒

࡞੒͢ΔΞϓϦ w 4UBDL0WFSqPX"1* w ΈΜͳେ޷͖ɺϓϩάϥϛϯάͷ2"αΠτ w QVCMJD"1*Ͱݕࡧ΍ৄࡉ͕औΕΔ

4UBDL0WFSqPX"1* w υΩϡϝϯτ w IUUQTBQJTUBDLFYDIBOHFDPNEPDT w TFBSDI"1* ྫλΠτϧʹBOESPJE w
IUUQTBQJTUBDLFYDIBOHFDPNTFBSDI PSEFSEFTDTPSUBDUJWJUZJOUJUMFBOESPJET JUFTUBDLPWFSqPXpMUFS GQO[U%1

4UBDLFS

"OESPJE

໨࣍ w "OESPJEͱ͸ʁ w ηοτΞοϓ w )FMMP8PSMEΛோΊΔ w ΞϓϦ࡞੒

"OESPJEͱ͸ w (PPHMFͷ04 w -JOVYΧʔωϧΛ࢖༻ w ༷ʑͳϝʔΧʔ w ೔ຊʹ͓͚ΔγΣΞ͸ w
࠷৽͸ NBSTINBMMPX

։ൃ؀ڥ w +BWB w ਖ਼֬ʹ͸"OESPJE+BWB  ͱݴΘΕɺڍಈ͕ҧͬͨΓ͢Δ w ਖ਼نදݱFUD w "OESPJE/͔Β͸0QFO+%,KBWB

։ൃ؀ڥ w "OESPJE4UVEJP w *OUFMMJ+ϕʔε w 8JOEPXTNBD-JOVY w ແྉ

ηοτΞοϓ

໊শઃఆ w ࠓճ͸4UBDLFS w OFUOPOZMFOFTUBDLFS w ͜Ε͕ΞϓϦͷ*%ʹ

04όʔδϣϯ w ݹ͍όʔδϣϯ͕ଟ͘ଘࡏ w ࠷৽ͷ"1*͕࢖͑ͳ͍౳ w Ҏ্ఔ౓͕Φεεϝ

"DUJWJUZ࡞੒ w &NQUZ"DUJWJUZΛબ୒  ʢ#BTJD͸ͪΐͬͱ"EWBODFE͗͢Δʣ

)FMMP8PSME w ୺຤Λ઀ଓɺ্ʹ͋Δl⾣z Λԡͯ͠ΞϓϦΛىಈ w ΤϛϡϨʔλͰ΋Մ

)FMMP8PSMEΛோΊΔ

.BJO"DUJWJUZKBWB public class MainActivity extends AppCompatActivity { @Override protected void
onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); } } ˣޙͰઆ໌ ˢϨΠΞ΢τΛදࣔ w ը໘੍ޚ

[email protected]YNMʢൈਮʣ <RelativeLayout android:layout_width="match_parent" android:layout_height="match_parent"> <TextView android:layout_width="wrap_content" android:layout_height="wrap_content" android:text="Hello World!"/> </RelativeLayout>
w ϨΠΞ΢τ

CVJMEHSBEF ൈਮ android { defaultConfig { applicationId "net.nonylene.stacker" minSdkVersion 19
targetSdkVersion 23 versionCode 1 versionName "1.0" } } dependencies { compile 'com.android.support:appcompat-v7:23.2.0' } ˡόʔδϣϯ৘ใͳͲ ˢ֎෦ϥΠϒϥϦ 4VQQPSU-JCSBSZ w Ϗϧυઃఆ౳ HSPPWZ

"OESPJE.BOJGFTUYNMʢൈਮʣ w ΞϓϦͷ৘ใ͕ॻ͔ΕͨϑΝΠϧ <manifest package=“net.nonylene.stacker"> <application android:allowBackup="true" android:icon="@mipmap/ic_launcher" android:label="@string/app_name" android:theme=“@style/AppTheme">
<activity android:name=".MainActivity"> <intent-filter> <action android:name="android.intent.action.MAIN"/> <category android:name  ="android.intent.category.LAUNCHER"/> </intent-filter> </activity> </application> </manifest> ˡΞϓϦ໊ɺΞΠίϯ౳ ˢ"DUJWJUZͷ৘ใ

ΞϓϦ࡞੒

ϑϩʔΛߟ͑Δ ᶃݕࡧϫʔυΛೖྗͤ͞Δ ᶅ"1*Λୟ͍ͯ݁ՌΛऔಘ ᶅ+40/Λॲཧ ᶆॲཧͨ݁͠ՌΛදࣔ͢Δ

ᶃݕࡧϫʔυΛೖྗ

ϨΠΞ΢τ࡞੒

ը໘Λ૊ΈཱͯΔ w ը໘ύʔπͷ͜ͱΛViewͱ͍͏ w "OESPJEͰ͸ը໘ύʔπ͸YNMͰද͞ΕΔ w ೖྗཝͱϦετදࣔͷύʔπΛ্Լʹฒ΂Δ

BDUJWJUZNBJOYNMʢൈਮʣ <LinearLayout android:layout_width="match_parent" android:layout_height="match_parent" android:orientation="vertical"> <EditText android:id="@+id/edit_text" android:layout_width="match_parent" android:layout_height="wrap_content" android:hint="Please
input search” android:lines=“1”/> <Button ~~~ android:text=“Search!”/> <android.support.v7.widget.RecyclerView ~~~ android:scrollbars=“vertical"/> </LinearLayout> ɾ-JOFBS-BZPVU &EJU5FYU #VUUPO 3FDZDMFS7JFX

-JOFBS-BZPVU w ෳ਺ͷViewΛ্ԼPSࠨӈʹฒ΂Δ໾ׂΛ࣋ͭ • layout_width=“match_parent”  layout_height=“match_parent”    ɹɹॎԣ͍ͬͺ͍ʹ޿͛Δ • orientation="vertical" 
  ɹɹॎ޲͖ʹฒ΂Δ

&EJU5FYU w จࣈೖྗ༻ͷView • id="@+id/edit_text"    ɹɹϓϩάϥϜ͔Βࢀর͢ΔͨΊͷ*% • hint=“Please input
search"    ɹɹ༧Ίදࣔ͢Δώϯτ • lines="1"    ɹɹҰߦදࣔ

&EJU5FYU • layout_width=“match_parent”  layout_height=“wrap_content”    ɹɹԣ෯͸͍ͬͺ͍ʹ޿͛Δ  ɹɹॎ෯͸σϑΥϧτͷߴ͞ʹ͢Δ • ࣗ෼Ͱߴ͞Λઃఆ͢Δ৔߹͸ dp
Λ࢖͏ • 1dp ͸୺຤ʹΑͬͯ 2px ͩͬͨΓ 3px ͩͬͨΓ

#VUUPO w Ϙλϯͷ7JFX • text=“Search!"    ɹɹϘλϯʹදࣔ͢ΔςΩετ

w 4VQQPSU-JCSBSZʹೖ͍ͬͯΔ w 4VQQPSU-JCSBSZͱ͸ɾɾɾʁ 3FDZDMFS7JFX

w ৽͍͠04ͷػೳͷҰ෦Λݹ͍04Ͱ΋࢖͑ΔΑ͏ʹ ͢ΔɺHPPHMFͷެࣜϥΠϒϥϦ w ྫ.BUFSJBM%FTJHO 'SBHNFOU FUD w ઌ΄ͲͷAppCompatActivity΋ͦͷҰͭ w
࠷৽ͷσβΠϯͷҰ෦΍ػೳ͕ఏڙ͞ΕΔ 4VQQPSU-JCSBSZ

w ଞʹ΋04ʹ͸ೖͬͯͳ͍ศརػೳΛఏڙ w ྫ3FDZDMFS7JFX 1BMFUUF 4VQQPSU-JCSBSZ

w ಉ͡ViewΛ܁Γฦ͠Ϧετදࣔ͢ΔView w ৄ͘͠͸ޙͰઆ໌ 3FDZDMFS7JFX

w ϥΠϒϥϦͱͯ͠഑෍͞Ε͍ͯΔͷͰಋೖ w CVJMEHSBEMF 3FDZDMFS7JFX dependencies { compile ‘com.android.support:appcompat-v7:23.2.0’ compile
‘com.android.support:recyclerview-v7:23.2.0' }

3FDZDMFS7JFX w [email protected]YNM <android.support.v7.widget.RecyclerView android:id="@+id/recycler_view" android:layout_width="match_parent" android:layout_height="match_parent" android:scrollbars=“vertical"/>

࣮ػͰ֬ೝ w Ϧετ෦෼͸ۭന w ԿΛදࣔͤ͞Δ͔Λ·ܾͩ Ί͍ͯͳ͍

ΫϦοΫˠจࣈྻऔಘ

ϑϩʔ w Ϣʔβʔ͕ϘλϯΛԡ͢  ˠEditText͔ΒݕࡧΩʔϫʔυΛऔಘ w ͦΕʹԠͯ͡(&53FRVFTUΛඈ͹͢ ᶄ

7JFXΛ"DUJWJUZ಺Ͱೝࣝ • View View#findViewById(int id) • YNMͰࢦఆͨ͠*%ͷ View Λऔಘ͢Δ •
ྫ: id=“@+id/view_id” ͱࢦఆ  → View view =  findViewById(R.layout.view_id); • R.layout.~~ ͸YNMͰ*%Λࢦఆ͢Δͱ  ࣗಈతʹ࡞ΒΕΔɺ*%ͷू߹Ϋϥε

Ωʔϫʔυऔಘ • ಘΒΕͨ View Λ EditText ʹΩϟετ  → EditText ͱͯ͠ϓϩάϥϜͰѻ͑Δ
public class MainActivity extends AppCompatActivity { @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); EditText editText = (EditText) findViewById(R.id.edit_text); Button button = (Button) findViewById(R.id.button); } }

ϘλϯͷΫϦοΫ • View View#setOnClickListener  (OnClickListener listener) • Click ͞Εͨ࣌ͷϦεφʔΛઃఆ •
ΫϦοΫ͞ΕΔ  → Ϧεφʔʹ͋Δࢦఆͷؔ਺͕ݺ͹ΕΔ • java7 ʹϥϜμࣜ͸ແ͍  → ແ໊ΦϒδΣΫτΛ࡞੒͢Δ

@Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); final EditText
editText = (EditText)  findViewById(R.id.edit_text); Button button = (Button) findViewById(R.id.button); button.setOnClickListener(new View.OnClickListener() { @Override public void onClick(View v) { String searchText =   editText.getText().toString(); } }); } • ΫϦοΫ͞ΕͨΒ OnClick ͕ݺ͹Εɺ  ɹEditText ͔ΒΩʔϫʔυऔಘ͢Δ

ᶄ"1*Ͱ+40/औಘ

ωοτϫʔΫ w ωοτϫʔΫΛඈ͹͢ʹ͸ݖݶ͕͍Δ w ΞϓϦͷݖݶ͸Πϯετʔϧ࣌ʹ֬ೝ͞ΕΔ w "OESPJE͔Β͸Ұ෦ͷݖݶ͕ڐՄ੍ʹ w "OESPJE.BOJGFTUYNMʹهड़

ωοτϫʔΫݖݶͷ௥Ճ w "OESPJE.BOJGFTUYNM <manifest package="net.nonylene.stacker"> <uses-permission android:name="android.permission.INTERNET"/> <uses-permission ɹ  ɹɹɹɹɹandroid:name="android.permission.ACCESS_NETWORK_STATE"/>
<application android:label="@string/app_name"> <activity android:name=".MainActivity"> </activity> </application> </manifest>

ωοτϫʔΫ w "OESPJEͷσϑΥϧτͰ͸%FGBVMU)UUQ$MJFOU ͱ"TZOD5BTL -PBEFS Λ࢖͏ w গ͠೉͍͠ͷͰࠓճ͸0L)UUQΛ࢖͏ w 4RVBSFࣾͷKBWB޲͚௨৴ϥΠϒϥϦ
w "OESPJE಺෦Ͱ΋࢖ΘΕ͍ͯΔ

0L)UUQ w build.gradleʹ௥Ճ dependencies { compile 'com.android.support:appcompat-v7:23.2.0' compile ‘com.android.support:recyclerview-v7:23.2.0' compile
'com.squareup.okhttp3:okhttp:3.2.0' }

ϦΫΤετΛ࡞੒ String encodedText = null; try { encodedText = URLEncoder.encode(text,
"utf-8"); } catch (UnsupportedEncodingException ignore) {} String url = "https://api.stackexchange.com/2.2/search? order=desc&sort=activity&intitle=" + encodedText + "&site=stackoverflow&filter=!-*f(6pnztD5P"; Request request = new Request.Builder() .url(url) .build(); w ϦΫΤετ͢Δ63-Λγϡοͱ࡞੒ ˡ0L)UUQʹ౉͢ϦΫΤετͷ৘ใ

ϦΫΤετΛ౤͛Δ w "OESPJEͰ͸6*ͷߋ৽ʹ࢖͏εϨου͸Ұͭ w ͜ͷεϨουҎ֎Ͱ6*ؔ܎Λ࿔ΔͱΤϥʔ w ωοτϫʔΫͷϦΫΤετ͸ɺ6*εϨουͰߦͬ ͯ͸͍͚ͳ͍ w ϦΫΤετʹ͕͔͔࣌ؒΔͱը໘͕ݻ·ΔͨΊ

0L)UUQΛ࢖ͬͨϦΫΤετ

new OkHttpClient().newCall(request).enqueue(new Callback() { @Override public void onFailure(Call call, IOException
e) { e.printStackTrace(); } @Override public void onResponse(Call call, final Response response)  throws IOException { final String body = response.body().string(); runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(MainActivity.this, body,   Toast.LENGTH_LONG).show(); } }); } }); • enqueue ʹ Callback Λ౉͢ͱ  ผεϨουͰ Request ͞ΕΔ

e) { e.printStackTrace(); } @Override public void onResponse(Call call, final Response response)  throws IOException { final String body = response.body().string(); runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(MainActivity.this, body,   Toast.LENGTH_LONG).show(); } }); } }); • runOnUiThread() ʹ Runnable Λ౉͢ͱ  6*εϨουͰ run() ͕࣮ߦ͞ΕΔ

e) { e.printStackTrace(); } @Override public void onResponse(Call call, final Response response)  throws IOException { final String body = response.body().string(); runOnUiThread(new Runnable() { @Override public void run() { Toast.makeText(MainActivity.this, body,   Toast.LENGTH_LONG).show(); } }); } }); • ड͚औͬͨ body Λͦͷ··τʔετʹग़͢

࣮ػͰ֬ೝ

ᶅ+40/Λॲཧ

+40/Λύʔε • JsonObject(String json) • String Λύʔε͠ Json ͱͯ͠ѻ͏ •
ྫ: String JsonObject#getString  (String name) • json ͷ name ͱ͍͏߲໨ͷจࣈྻΛऔಘ

• ฦ͖ͬͯͨ Response Λ   JsonObject ʹม׵ɺͦͷதͷ “items” Λऔಘ @Override
public void onResponse(Call call, final Response response) throws … { final String body = response.body().string(); try { JSONObject json = new JSONObject(body); JSONArray questionsJson = json.getJSONArray("items"); } catch (JSONException ignore) {} }

σʔλอ࣋Ϋϥε

σʔλอ࣋Ϋϥε w ฦ͖ͬͯͨ+40/ΛಡΈࠐΈɺΫϥεʹ֨ೲ͢Δ w σʔλΛѻ͍΍͘͢͢ΔͨΊ

σʔλอ࣋Ϋϥε • Question ΫϥεΛ࡞Δ • Question.java Λ࡞੒

public class Question { public final boolean isAnswered; public final
String ownerName; public final int upVoteCount; public final Date creationDate; public final String title; public Question(JSONObject json) throws ɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹɹJSONException { isAnswered = ɹɹɹ ɹɹɹɹɹɹɹjson.getBoolean(“is_answered"); upVoteCount =   ɹɹɹɹɹɹɹjson.getInt(“up_vote_count"); creationDate = new Date(  ɹɹɹɹɹɹɹjson.getInt("creation_date")  ɹɹɹɹɹɹɹ * 1000); title = json.getString(“title"); JSONObject owner =   ɹɹɹɹɹɹɹjson.getJSONObject("owner"); ownerName =   ɹɹɹɹɹɹɹowner.getString("display_name"); } }

KTPOΛ2VFTUJPOʹม׵

• json ͷ഑ྻͷཁૉ͢΂ͯΛ Question ʹม׵ @Override public void onResponse(Call call,
final Response response) throws … { final String body = response.body().string(); try { JSONObject json = new JSONObject(body); JSONArray questionsJson = json.getJSONArray("items"); final List<Question> questions = new ArrayList<>(); for (int i = 0; i < questionsJson.length(); i++) { questions.add(new Question(questionsJson.getJSONObject(i))); } runOnUiThread(new Runnable() { … Toast.makeText(MainActivity.this, questions.get(0).title,   Toast.LENGTH_LONG).show(); }); } catch (JSONException ignore) {} }

• Ұ൪໨ͷ Question ͷλΠτϧΛτʔετදࣔ @Override public void onResponse(Call call, final
Response response) throws … { final String body = response.body().string(); try { JSONObject json = new JSONObject(body); JSONArray questionsJson = json.getJSONArray("items"); final List<Question> questions = new ArrayList<>(); for (int i = 0; i < questionsJson.length(); i++) { questions.add(new Question(questionsJson.getJSONObject(i))); } runOnUiThread(new Runnable() { … Toast.makeText(MainActivity.this, questions.get(0).title,   Toast.LENGTH_LONG).show(); }); } catch (JSONException ignore) {} }

࣮ػͰ֬ೝ

ᶆॲཧͨ݁͠ՌΛදࣔ

3FDZDMFS7JFX ಉ͡7JFXΛ܁Γฦ͠Ϧετදࣔ͢Δ7JFX

3FDZDMFS7JFX ී௨ʹ্͔ΒViewΛஔ͚͹͍͍͡ΌΜʁ

w ⚠ཁૉ͕ݸҎ্ʹͳΔ͜ͱ΋ w ྫ5XJUUFS w ͜ͷ࣌ݸಉ࣌ʹViewΛอ࣋ɾ؅ཧ͢Δʁ  ˠ๲େͳϝϞϦɾॲཧΛফඅͯ͠͠·͏ 3FDZDMFS7JFX

w Ϧετදࣔ͸ಉ͡ߏ଄ͷView͕࿈ͳΔ w จࣈྻ౳ͷ಺༰͕ҧ͏͚ͩ ˠɹอ࣋ɾ؅ཧ͸ը໘ʹදࣔ͞ΕΔViewͷΈ ˠɹҰ౓࡞ͬͨ7JFX͸࠶ར༻͠ɺ  දࣔ࣌ʹ಺༰Λมߋ͢Δ 3FDZDMFS7JFX

w ͢΂ͯΛอ࣋ɾ؅ཧ ී௨ͷ7JFX View 1 2 3 4 5 6
7 8 9 10 11 12 13 14 15 16 17 18 ࣮ࡍͷදࣔྖҬ →

w อ࣋ɾ؅ཧ͸ը໘্ͷΈ 3FDZDMFS7JFX View 3 4 5 6 7 8
9 10 11 ະੜ੒ ࣮ࡍͷදࣔྖҬ →

εΫϩʔϧ͞ΕΔͱʜ View 3 4 5 6 7 8 9 10
11 ະੜ੒ View ͷ࠶ར༻ දࣔྖҬ →

εΫϩʔϧ͞ΕΔͱʜ View 5 6 7 8 9 10 11 3
->12 4 ->13 ະੜ੒ ← ৽͍͠஋Λઃఆ දࣔྖҬ →

3FDZDMFS7JFX ࠶ར༻

w ListView͕ݩʑ͋ͬͨʢ͜Ε΋࠶ར༻Մೳʣ w ͦͷڧԽɾΧελϚΠζՄೳ൛ 3FDZDMFS7JFX

Ϧετදࣔ ߲໨ͷViewΛ࡞੒ ˣ RecyclerViewʹදࣔ

߲໨ͷ7JFXʢলུʣ

w ཁૉΛදࣔ͢Δͱ͖ʹViewHolder͕߱ͬͯ͘Δ w ੜ੒PS࠶ར༻͞ΕͨViewΛؚΉΫϥε w 7JFX)PMEFSࣗମ΋࠶ར༻͞Εͨ΋ͷ w ͜ΕΛ༻͍ͯ಺༰Λઃఆ͢Δ 3FDZDMFS7JFXʹදࣔ

w ViewͷछྨผʹͦΕͧΕViewHolderΛ࡞Δ w ࠓճ͸Ұ͚ͭͩ 7JFX)PMEFS࡞੒

w ࠷ॳʹView͕ੜ੒͞ΕΔͱ͖ʹݺ͹ΕΔ w findViewById΋ੜ੒࣌ʹҰ౓͚ͩߦ͏ private class QuestionViewHolder extends RecyclerView.ViewHolder {
private final TextView mCountView; private final TextView mTitleView; … public QuestionViewHolder(View itemView) { super(itemView); mCountView = (TextView) itemView.findViewById(R.id.count); mTitleView = (TextView) itemView.findViewById(R.id.title); … } public void bindView(Question question) { mCountView.setText(String.valueOf(question.upVoteCount)); mTitleView.setText(question.title); … itemView.setOnClickListener(new View.OnClickListener(){ … Intent intent = new Intent(Intent.ACTION_VIEW,  Uri.parse(question.link)); v.getContext().startActivity(intent); }); } } }

private class QuestionViewHolder extends RecyclerView.ViewHolder { private final TextView mCountView;
private final TextView mTitleView; … public QuestionViewHolder(View itemView) { super(itemView); mCountView = (TextView) itemView.findViewById(R.id.count); mTitleView = (TextView) itemView.findViewById(R.id.title); … } public void bindView(Question question) { mCountView.setText(String.valueOf(question.upVoteCount)); mTitleView.setText(question.title); … itemView.setOnClickListener(new View.OnClickListener(){ … Intent intent = new Intent(Intent.ACTION_VIEW,  Uri.parse(question.link)); v.getContext().startActivity(intent); }); } } } w View಺෦ͷ஋Λઃఆ

private class QuestionViewHolder extends RecyclerView.ViewHolder { private final TextView mCountView;
private final TextView mTitleView; … public QuestionViewHolder(View itemView) { super(itemView); mCountView = (TextView) itemView.findViewById(R.id.count); mTitleView = (TextView) itemView.findViewById(R.id.title); … } public void bindView(Question question) { mCountView.setText(String.valueOf(question.upVoteCount)); mTitleView.setText(question.title); … itemView.setOnClickListener(new View.OnClickListener(){ … Intent intent = new Intent(Intent.ACTION_VIEW,  Uri.parse(question.link)); v.getContext().startActivity(intent); }); } } } w ΫϦοΫͨ͠Β࣭໰ϖʔδΛ։͘Α͏ʹ͢Δ  ҉໧తIntentΛ౤͛Δ

w RecyclerViewΛૢ࡞͢ΔΫϥε 3FDZDMFS"EBQUFS࡞੒

w දࣔ͢ΔQuestionͷϦετ public class QuestionsRecyclerAdapter extends  RecyclerView.Adapter<RecyclerView.ViewHolder> { private List<Question>
mQuestionList = new ArrayList<>(); @Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View questionView = LayoutInflater.from(parent.getContext())  .inflate(R.layout.question_item, parent, false); return new QuestionViewHolder(questionView); } @Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { ((QuestionViewHolder) holder).bindView(mQuestionList.get(position)); } public void setQuestionList(List<Question> questionList) { mQuestionList = questionList; notifyDataSetChanged(); } @Override public int getItemCount() { return mQuestionList.size(); } }

w ͜͜ͰViewHolderΛ࡞੒͢Δ w ϨΠΞ΢τΛੜ੒ˠViewHolderΛ࡞੒ public class QuestionsRecyclerAdapter extends  RecyclerView.Adapter<RecyclerView.ViewHolder> {
private List<Question> mQuestionList = new ArrayList<>(); @Override public RecyclerView.ViewHolder onCreateViewHolder(ViewGroup parent, int viewType) { View questionView = LayoutInflater.from(parent.getContext())  .inflate(R.layout.question_item, parent, false); return new QuestionViewHolder(questionView); } @Override public void onBindViewHolder(RecyclerView.ViewHolder holder, int position) { ((QuestionViewHolder) holder).bindView(mQuestionList.get(position)); } public void setQuestionList(List<Question> questionList) { mQuestionList = questionList; notifyDataSetChanged(); } @Override public int getItemCount() { return mQuestionList.size(); } }

w position൪໨ͷViewͷ಺༰Λઃఆ͢Δ w ͜͜ͰViewHolderͷbindViewΛݺΜͰ͍Δ public class QuestionsRecyclerAdapter extends  RecyclerView.Adapter<RecyclerView.ViewHolder> {

w notifyDataSetChanged() Λߦ͏͜ͱͰ  RecyclerViewʹมߋΛ௨஌͢Δ public class QuestionsRecyclerAdapter extends  RecyclerView.Adapter<RecyclerView.ViewHolder> {

w RecyclerViewʹRecyclerAdapterΛηοτ 3FDZDMFS7JFX΁ઃఆ public class MainActivity extends AppCompatActivity { private
QuestionsRecyclerAdapter mQuestionsRecyclerAdapter; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); … RecyclerView recyclerView = (RecyclerView) findViewById(R.id.recycler_view); recyclerView.setLayoutManager(new LinearLayoutManager(this)); mQuestionsRecyclerAdapter = new QuestionsRecyclerAdapter(); recyclerView.setAdapter(mQuestionsRecyclerAdapter); } }

w RecyclerAdapterʹQuestionΛηοτ 2VFTUJPOΛઃఆ @Override public void onResponse(Call call, final Response
response) throws IOException { final String body = response.body().string(); try { JSONObject json = new JSONObject(body); ɹɹɹɹɹJSONArray questionsJson = json.getJSONArray("items"); final List<Question> questions = new ArrayList<>(); ɹɹɹɹɹfor (int i = 0; i < questionsJson.length(); i++) { questions.add(new Question(questionsJson.getJSONObject(i))); } runOnUiThread(new Runnable() … mQuestionsRecyclerAdapter.setQuestionList(questions); ); } catch (JSONException ignore) {} }

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Android・iOS アプリ作成入門 Android 編

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