我是android和java的新手，我在这个android项目上工作，我有一个ListView电影（Name-String，Genre-String，Year-Int）。我想在将项目传递给另一个activity之后拆分该项目。
我的电影模型：
public class Movie
{
// property to help us handle the data
private int id;
private String name;
private String genre;
private int year;
//Getters and Setters of the properties
public long getId()
{
return id;
}
public void setId(int id)
{
this.id = id;
}
public String getName()
{
return name;
}
public void setName(String name)
{
this.name = name;
}
public String getGenre()
{
return genre;
}
public void setGenre(String genre)
{
this.genre = genre;
}
public int getYear()
{
return year;
}
public void setYear(int year)
{
this.year = year;
}
public String toString()
{
return name + ", " + genre + ", " + year;
}
//----------Start--------- Here we have defined the table contents (basically a blueprint of the table Movie) -------------------------------------
public static final String TABLE_NAME = "movie";
public static final String COlUMN_ID = "id";
public static final String COlUMN_NAME = "make";
public static final String COlUMN_GENRE = "model";
public static final String COlUMN_YEAR = "year";
//----------------------END----------------------------------------------------------------------------------------------------------------//
}
我的创建电影活动：
public class CreateMovieActivity extends AppCompatActivity
{
MoviesRepository moviesRepository;
protected void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_create_movie);
moviesRepository = new MoviesRepository(this);
moviesRepository.open();
}
public void onClickSaveMovie(View v)
{
Button buttonAdd = (Button) v;
EditText editTextName = (EditText) findViewById(R.id.editTextName);
EditText editTextGenre = (EditText) findViewById(R.id.editTextGenre);
EditText editTextYear = (EditText) findViewById(R.id.editTextYear);
Movie movie = new Movie();
movie.setName(editTextName.getText().toString());
movie.setGenre(editTextGenre.getText().toString());
movie.setYear(Integer.parseInt(editTextYear.getText().toString()));
moviesRepository.Create(movie);
Button buttonCreate = (Button) v;
startActivity(new Intent(getBaseContext(),MainActivity.class));
}
}
我的电影资料库：
public class MoviesRepository
{
private SQLiteDatabase db;
private MyDBHelper myDBHelper;
private String [] MovieAllColumns ={Movie.COlUMN_ID,
Movie.COlUMN_NAME,
Movie.COlUMN_GENRE,
Movie.COlUMN_YEAR};
public MoviesRepository(Context context)
{
myDBHelper = new MyDBHelper(context);
}
public void open() throws SQLException
{
//Open connection to write data
db = myDBHelper.getWritableDatabase();
}
public void close()
{
//Close connection to database
db.close();
}
private Movie cursorToMovie (Cursor cursor)
{
Movie movie = new Movie();
movie.setId(cursor.getInt(0));
movie.setName(cursor.getString(1));
movie.setGenre(cursor.getString(2));
movie.setYear(cursor.getInt(3));
return movie;
}
public List<Movie> getAllMovies()
{
open();
List<Movie> movieList = new ArrayList<>();
Cursor cursor = db.query(Movie.TABLE_NAME, MovieAllColumns, null, null, null, null, null);
cursor.moveToFirst();
while (!cursor.isAfterLast())
{
Movie movie = cursorToMovie(cursor);
movieList.add(movie);
cursor.moveToNext();
}
cursor.close();
close();
return movieList;
}
public void Create(Movie movie)
{
open();
//helps you insert values to the table
ContentValues values = new ContentValues();
//Put method - first column; what column do you want to be storing this ind. Second; what is the value you want to put ind
values.put(Movie.COlUMN_NAME, movie.getName());
values.put(Movie.COlUMN_GENRE, movie.getGenre());
values.put(Movie.COlUMN_YEAR, movie.getYear());
db.insert(Movie.TABLE_NAME, null, values);
close();
}
public void Delete(Movie movie)
{
open();
//Deletes Movie by id
db.delete(Movie.TABLE_NAME, Movie.COlUMN_ID + " = " + movie.getId(), null);
db.close();
}
}
当我点击ListView上的某个项目时，它会将该值传递给另一个Activity，我可以将其打印出来（制作吐司）。
这是我将项目传递给其他意图的地方：
public void Select()
{
moviesRepository = new MoviesRepository(this);
moviesRepository.open();
final Movie movie;
final ListView listView = (ListView) findViewById(R.id.ListViewMovie);
listView.setOnItemClickListener(new AdapterView.OnItemClickListener()
{
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id)
{
final String details = listView.getAdapter().getItem(position).toString();
Intent i = new Intent(getApplicationContext(), MovieDetailsActivity.class);
i.putExtra("key", details);
startActivity(i);
}
});
}
但是如何从ListView拆分传递的值，这样才有意义。
这是我想要分成三个值的地方，电影名称，电影类型和年份：
public class MovieDetailsActivity extends AppCompatActivity
{
TextView movieName;
TextView movieGenre;
TextView movieYear;
@Override
protected void onCreate(@Nullable Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.movie_details);
getDetails();
}
public void getDetails()
{
movieName = (TextView) findViewById(R.id.textViewMovieName);
movieGenre = (TextView) findViewById(R.id.textViewMovieGenre);
movieYear = (TextView) findViewById(R.id.textViewMovieYear);
String data = getIntent().getExtras().getString("key");
Toast.makeText(this, data, Toast.LENGTH_LONG).show();
}
}
现在我正在为传递的项目致敬
答案 0 :(得分：0)
创建一个Apod类，它是单例并具有moviemanager。将电影保存为map到地图中。然后你可以调用<String, Movie>来获取电影对象。
答案 1 :(得分：0)
您正在询问如何在详细信息屏幕中拆分您收到的字符串。
实际上很简单; - ）
在MovieDetailsActivity#getDetails中，当您从Intent获得详细信息字符串时，您需要执行以下操作：
String data = getIntent().getExtras().getString("key");
String[] splitMovieString = data.split(", ");
然后你可以这样设置TextView：
movieName.setText(splitMovieString[0]);
movieGenre.setText(splitMovieString[1]);
movieYear.setText(splitMovieString[2]);
旁注：
通过Intent以字符串形式发送数据的方法是可以的，但它不是Android中在活动之间传递数据的首选方式。
有一种方法可以传递整个Movie对象，但前提是您更改对象以实现Parcelable接口。 （见the official documentation for a full example）
实施Parcelable后，您的Movie对象将如下所示：
public class Movie implements Parcelable {
private int id;
private String name;
private String genre;
private int year;
protected Movie(Parcel in) {
id = in.readInt();
name = in.readString();
genre = in.readString();
year = in.readInt();
}
public static final Creator<Movie> CREATOR = new Creator<Movie>() {
@Override
public Movie createFromParcel(Parcel in) {
return new Movie(in);
}
@Override
public Movie[] newArray(int size) {
return new Movie[size];
}
};
@Override
public int describeContents() {
return 0;
}
@Override
public void writeToParcel(Parcel parcel, int i) {
parcel.writeInt(id);
parcel.writeString(name);
parcel.writeString(genre);
parcel.writeInt(year);
}
[... Setters, getters and your constants are removed for brevity]
}
现在，您稍后更改了模型后，可以直接通过Intent系统传递它：
在Select内的OnClickListener方法中，您需要稍后更改Intent：
@Override
public void onItemClick(AdapterView<?> parent, View view, int position, long id) {
final Movie selectedMovie = listView.getAdapter().getItem(position);
Intent detailsIntent = new Intent(getApplicationContext(), MovieDetailsActivity.class);
detailsIntent.putExtra(Movie.class.getName(), selectedMovie);
startActivity(detailsIntent);
}
这里发生的事情是我们基本上＆＃34;压扁＆＃34; （或序列化）Movie对象到可以通过Intent系统发送的对象中。
现在当您收到Intent中的MovieDetailsActivity#getDetails时，您需要打开（或反序列化）＆＃34;展平的＆＃34;再次Movie个对象，这样您就可以像普通Movie对象一样使用它。
所以现在你的MovieDetailsActivity#getDetails应该是这样的：
public void getDetails() {
movieName = (TextView) findViewById(R.id.textViewMovieName);
movieGenre = (TextView) findViewById(R.id.textViewMovieGenre);
movieYear = (TextView) findViewById(R.id.textViewMovieYear);
Movie movie = getIntent().getParcelableExtra(Movie.class.getName());
// Now you can set your movie name, genre and year directly from your object.
movieName.setText(movie.getName());
movieGenre.setText(movie.getGenre());
movieYear.setText(String.valueOf(movie.getYear()); // Notice you cannot set an Integer directly as the text of a `TextView`, you need to parse it as a String first.
}
我知道最后一个解决方案会为您的课程带来更多代码，但这确实是实现此目的的最佳方式，当您使模型类实现Parcelable界面时，Android Studio会告诉您＃39 ;错过了实施，并实际问你是否需要帮助实施Parcelable，所以你不必自己做很多事情。
最后需要注意的是另一个解决方案，那就是将当前id的{{1}}传递到Movie，然后从Intent获取}直接在MoviesRepository中，但是您还必须使用可以从您的回购中获取单个MovieDetailsActivity的新方法扩展您的MoviesRepository。
我知道这是一个很长的答案，但这里有许多概念需要处理： - ）