Androidの学習をはじめて10日くらいの人の問題集

startActivityForResultを用いてデータの授受をしてみよう。

Q1
リストビューを使い英単語の一覧を表示する。
英単語の追加と編集の機能を実装すること。
詳しくは実行例を参照せよ。

[実行例]

スタート画面

登録を押すと画面遷移して入力フォームが表示される。

フォームに入力し、追加ボタンを押すと・・・

リストに表示される。

項目タップでカスタマイズされたトーストにて単語と意味が表示される。

リスト項目を長押しすると遷移して編集画面へ

編集し更新ボタンを押すと・・・

更新される。

●activity_main.xml

01<?xml version="1.0" encoding="utf-8"?>
02<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
03    xmlns:app="http://schemas.android.com/apk/res-auto"
04    android:layout_width="match_parent"
05    android:layout_height="match_parent"
06    >
07 
08    <ListView
09        android:layout_width="368dp"
10        android:layout_height="400dp"
11        android:layout_marginLeft="8dp"
12        android:layout_marginRight="8dp"
13        android:layout_marginTop="8dp"
14        app:layout_constraintLeft_toLeftOf="parent"
15        app:layout_constraintRight_toRightOf="parent"
16        app:layout_constraintTop_toTopOf="parent"
17        android:layout_marginStart="8dp"
18        android:layout_marginEnd="8dp"
19        android:id="@+id/lv" />
20 
21    <Button
22        android:id="@+id/button"
23        android:layout_width="0dp"
24        android:layout_height="wrap_content"
25        android:layout_marginLeft="16dp"
26        android:layout_marginRight="8dp"
27        android:layout_marginTop="12dp"
28        android:onClick="btClick"
29        android:text="登録"
30        app:layout_constraintHorizontal_bias="0.0"
31        app:layout_constraintLeft_toLeftOf="parent"
32        app:layout_constraintRight_toRightOf="parent"
33        app:layout_constraintTop_toBottomOf="@+id/lv" />
34</android.support.constraint.ConstraintLayout>

●activity_sub.xml

01<?xml version="1.0" encoding="utf-8"?>
02<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
03    xmlns:app="http://schemas.android.com/apk/res-auto"
04    android:layout_width="match_parent"
05    android:layout_height="match_parent"
06    >
07 
08    <TextView
09        android:id="@+id/textView"
10        android:layout_width="36dp"
11        android:layout_height="wrap_content"
12        android:text="単語"
13        android:textSize="18sp"
14        app:layout_constraintBaseline_toBaselineOf="@+id/etWord"
15        android:layout_marginLeft="16dp"
16        app:layout_constraintLeft_toLeftOf="parent" />
17 
18    <EditText
19        android:id="@+id/etWord"
20        android:layout_width="wrap_content"
21        android:layout_height="wrap_content"
22        android:layout_marginLeft="8dp"
23        android:ems="10"
24        android:inputType="textPersonName"
25        app:layout_constraintLeft_toRightOf="@+id/textView"
26        app:layout_constraintTop_toTopOf="parent"
27        android:layout_marginTop="16dp" />
28 
29    <TextView
30        android:id="@+id/textView2"
31        android:layout_width="wrap_content"
32        android:layout_height="wrap_content"
33        android:text="意味"
34        android:textSize="18sp"
35        android:layout_marginLeft="16dp"
36        app:layout_constraintLeft_toLeftOf="parent"
37        app:layout_constraintBaseline_toBaselineOf="@+id/etBody" />
38 
39    <EditText
40        android:id="@+id/etBody"
41        android:layout_width="wrap_content"
42        android:layout_height="wrap_content"
43        android:layout_marginLeft="8dp"
44        android:layout_marginTop="8dp"
45        android:ems="10"
46        android:inputType="textMultiLine|textPersonName"
47        android:maxLines="5"
48        android:minLines="2"
49        android:singleLine="false"
50        app:layout_constraintLeft_toRightOf="@+id/textView2"
51        app:layout_constraintTop_toBottomOf="@+id/etWord" />
52 
53    <Button
54        android:id="@+id/btAction"
55        android:layout_width="wrap_content"
56        android:layout_height="wrap_content"
57        android:layout_marginLeft="8dp"
58        android:layout_marginRight="8dp"
59        android:layout_marginTop="8dp"
60        android:onClick="btAction"
61        android:text="追加"
62        android:textSize="18sp"
63        app:layout_constraintLeft_toLeftOf="parent"
64        app:layout_constraintRight_toRightOf="parent"
65        app:layout_constraintTop_toBottomOf="@+id/etBody" />
66</android.support.constraint.ConstraintLayout>

●toast_view.xml

01<?xml version="1.0" encoding="utf-8"?>
02<android.support.constraint.ConstraintLayout xmlns:android="http://schemas.android.com/apk/res/android"
03    xmlns:app="http://schemas.android.com/apk/res-auto"
04    android:layout_width="match_parent"
05    android:layout_height="match_parent"
06    android:background="@android:color/holo_orange_light"
07    android:paddingRight="16dp">
08 
09    <TextView
10        android:id="@+id/textView3"
11        android:layout_width="wrap_content"
12        android:layout_height="wrap_content"
13        android:layout_marginLeft="16dp"
14        android:text="単語"
15        android:textSize="18sp"
16        app:layout_constraintBaseline_toBaselineOf="@+id/tvWord"
17        app:layout_constraintLeft_toLeftOf="parent" />
18 
19    <TextView
20        android:id="@+id/tvWord"
21        android:layout_width="wrap_content"
22        android:layout_height="wrap_content"
23        android:layout_marginLeft="8dp"
24        android:layout_marginTop="16dp"
25        android:text="TextView"
26        android:textSize="18sp"
27        app:layout_constraintLeft_toRightOf="@+id/textView3"
28        app:layout_constraintTop_toTopOf="parent" />
29 
30    <TextView
31        android:id="@+id/textView5"
32        android:layout_width="wrap_content"
33        android:layout_height="wrap_content"
34        android:layout_marginLeft="16dp"
35        android:layout_marginTop="8dp"
36        android:text="意味"
37        android:textSize="18sp"
38        app:layout_constraintLeft_toLeftOf="parent"
39        app:layout_constraintTop_toBottomOf="@+id/textView3" />
40 
41    <TextView
42        android:id="@+id/tvBody"
43        android:layout_width="wrap_content"
44        android:layout_height="wrap_content"
45        android:layout_marginBottom="16dp"
46        android:layout_marginLeft="8dp"
47        android:layout_marginTop="8dp"
48        android:maxLines="5"
49        android:minLines="2"
50        android:text="TextView"
51        android:textSize="18sp"
52        app:layout_constraintBottom_toBottomOf="parent"
53        app:layout_constraintLeft_toRightOf="@+id/textView5"
54        app:layout_constraintTop_toBottomOf="@+id/tvWord" />
55</android.support.constraint.ConstraintLayout>

●Word.java

01import java.io.Serializable;
02 
03 
04public class Word implements Serializable{
05 
06    private String word;
07    private String body;
08 
09    public Word(String word, String body) {
10        setWord(word);
11        setBody(body);
12    }
13 
14    @Override
15    public String toString() {
16        return this.getWord();
17    }
18    public void setWord(String word){
19        this.word=word;
20    }
21    public void setBody(String body){
22        this.body=body;
23    }
24 
25    public String getBody() {
26        return this.body;
27    }
28    public String getWord(){
29        return this.word;
30    }
31 
32 
33 
34}

●MainActivity.java

01import android.content.Intent;
02import android.os.Bundle;
03import android.support.v7.app.AppCompatActivity;
04import android.view.Gravity;
05import android.view.LayoutInflater;
06import android.view.View;
07import android.widget.AdapterView;
08import android.widget.ArrayAdapter;
09import android.widget.ListView;
10import android.widget.TextView;
11import android.widget.Toast;
12 
13import java.util.ArrayList;
14import java.util.List;
15 
16public class MainActivity extends AppCompatActivity {
17    private ListView lv;
18    private TextView tvWord,tvBody;
19    private ArrayAdapter<Word> adapter;
20    private List<Word> list=new ArrayList<>();
21    private Toast toast;
22    public static final int WORD_ADD=1,WORD_EDIT=2;
23 
24    @Override
25    protected void onCreate(Bundle savedInstanceState) {
26        super.onCreate(savedInstanceState);
27        setContentView(R.layout.activity_main);
28        lv=(ListView)findViewById(R.id.lv);
29        createToast();
30        adapter=new ArrayAdapter<>(this,android.R.layout.simple_list_item_1,list);
31        lv.setAdapter(adapter);
32        lv.setOnItemClickListener(new AdapterView.OnItemClickListener() {
33            @Override
34            public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
35                Word w=list.get(position);
36                tvWord.setText(w.getWord());
37                tvBody.setText(w.getBody());
38                toast.show();
39 
40            }
41        });
42        lv.setOnItemLongClickListener(new AdapterView.OnItemLongClickListener() {
43            @Override
44            public boolean onItemLongClick(AdapterView<?> parent, View view, int position, long id) {
45                Word w=list.get(position);
46                Intent i=new Intent(MainActivity.this,SubActivity.class);
47                i.putExtra("index",position);
48                i.putExtra("word",w);
49                i.putExtra("requestCode",WORD_EDIT);
50                startActivityForResult(i,WORD_EDIT);
51                return true;
52            }
53        });
54    }
55 
56    private void createToast() {
57        LayoutInflater inflater=getLayoutInflater();
58        View view=inflater.inflate(R.layout.toast_view,null);
59        tvWord=(TextView)view.findViewById(R.id.tvWord);
60        tvBody=(TextView)view.findViewById(R.id.tvBody);
61        toast=new Toast(this);
62        toast.setView(view);
63        toast.setDuration(Toast.LENGTH_LONG);
64        toast.setGravity(Gravity.CENTER,0,0);
65 
66    }
67 
68    public void btClick(View v){
69        Intent i=new Intent(this,SubActivity.class);
70        i.putExtra("requestCode",WORD_ADD);
71        startActivityForResult(i,WORD_ADD);
72    }
73 
74    @Override
75    protected void onActivityResult(int requestCode, int resultCode, Intent data) {
76        super.onActivityResult(requestCode, resultCode, data);
77        if(resultCode==RESULT_OK) {
78            Word w = (Word) data.getSerializableExtra("word");
79            switch (requestCode) {
80                case WORD_ADD:
81                    list.add(w);
82                    break;
83                case WORD_EDIT:
84                    int index = data.getIntExtra("index", -1);
85                    list.set(index, w);
86                    break;
87            }
88            adapter.notifyDataSetChanged();
89        }
90    }
91 
92 
93}

●SubActivity.java

01import android.content.Intent;
02import android.os.Bundle;
03import android.support.v7.app.AppCompatActivity;
04import android.view.View;
05import android.widget.Button;
06import android.widget.EditText;
07 
08public class SubActivity extends AppCompatActivity {
09    private EditText etWord, etBody;
10    private Button btAction;
11    private int requestCode;
12    private Word w;
13    private int index;
14 
15    @Override
16    protected void onCreate(Bundle savedInstanceState) {
17        super.onCreate(savedInstanceState);
18        setContentView(R.layout.activity_sub);
19        etWord = (EditText) findViewById(R.id.etWord);
20        etBody = (EditText) findViewById(R.id.etBody);
21        btAction = (Button) findViewById(R.id.btAction);
22        Intent i = this.getIntent();
23        requestCode = i.getIntExtra("requestCode", MainActivity.WORD_ADD);
24        switch (requestCode) {
25 
26            case MainActivity.WORD_EDIT:
27 
28                w = (Word) i.getSerializableExtra("word");
29                index=i.getIntExtra("index",-1);
30                etWord.setText(w.getWord());
31                etBody.setText(w.getBody());
32                btAction.setText("更新");
33                break;
34        }
35 
36    }
37 
38    public void btAction(View v) {
39        String word=etWord.getText().toString();
40        String body=etBody.getText().toString();
41        Intent i=new Intent();
42        switch (this.requestCode) {
43            case MainActivity.WORD_ADD:
44                w=new Word(word,body);
45                break;
46            case MainActivity.WORD_EDIT:
47                w.setWord(word);
48                w.setBody(body);
49                i.putExtra("index",index);
50                break;
51 
52        }
53 
54        i.putExtra("word",w);
55        setResult(RESULT_OK,i);
56        finish();
57    }
58 
59 
60}