Question

我创建了一个实现了Parcelable的“ Item”类，并设置了他的构造器

public Item(Parcel in) {
    this.mName = in.readString();
    this.mFilePath = in.readString();
    this.mId = in.readInt();
    this.mLength = in.readInt();
    this.mTime = in.readLong();
}

我的问题是，当我使用该类时，我不知道如何传递参数，例如波纹管：

 Item item = new  Item(//What to put her!); 
    item.setId(c.getInt(c.getColumnIndex("_id")));
    item.setName(c.getString(c.getColumnIndex(DBHelperItem.COLUMN_NAME_RECORDING_NAME)));
    item.setFilePath(c.getString(c.getColumnIndex(DBHelperItem.COLUMN_NAME_RECORDING_FILE_PATH)));
    item.setLength(c.getInt(c.getColumnIndex(DBHelperItem.COLUMN_NAME_RECORDING_LENGTH)));
    item.setTime(c.getLong(c.getColumnIndex(DBHelperItem.COLUMN_NAME_TIME_ADDED))); 
return item;

Answer 1

Parcel.writeStringArray

使用Parcel.writeStringArray捆绑您的字符串，然后将其粘贴到构造函数中

Answer 2

您可以在Item类中具有其他构造函数

public Item(mName,mFilepath,mId,mLength,mTime) {
    this.mName = mname;
    this.mFilePath = mFilepath;
    this.mId = mId;
    this.mLength = mLength;
    this.mTime = mTime;
}

在您的活动中初始化项目中的所有字段

 int id=(c.getInt(c.getColumnIndex("_id")));
 String name =   
  (c.getString(c.getColumnIndex(DBHelperItem.COLUMN_NAME_RECORDING_NAME)));
 String filePath=     
  (c.getString(c.getColumnIndex(DBHelperItem.COLUMN_NAME_RECORDING_FILE_PATH)));
 int length=     
  (c.getInt(c.getColumnIndex(DBHelperItem.COLUMN_NAME_RECORDING_LENGTH)));
 double time =    
  (c.getLong(c.getColumnIndex(DBHelperItem.COLUMN_NAME_TIME_ADDED)));

现在您可以使用以上字段创建新项目

Item item = new Item（id，name，filePath，lenfth，time）;

以下是我使用Parcelable的示例：https://github.com/riyaza15/ParcelableDemo enter code here

Answer 3

Item.java

public class Item {

    private String mName;
    private String mFilePath;
    private int mId;
    private int mLength;
    private long mTime;

    public Item(Parcel in) {
        this.mName = in.readString();
        this.mFilePath = in.readString();
        this.mId = in.readInt();
        this.mLength = in.readInt();
        this.mTime = in.readLong();
    }
}

Parcel.java（根据我们从您的代码中看到的内容，它应该包含以下方法）

public class Parcel {

    public String readString() {

        //read a string
        return null;
    }

    public int readInt() {

        //read an int
        return 0;
    }

    public long readLong() {

        //read a long
        return 0;
    }
}

Test.java（您的主要方法所驻留的）

public class Test {

    public static void main(String[] args) {


        Parcel p = new Parcel();

        /*Pass the parcel like this*/

        Item item = new Item(p);

        /*
         * 
         * Rest of the code
         * 
         * */
    }
}

也许您的方法定义与提供的代码不同。您应该相应地更改它们。

将参数传递给参数

3 个答案: