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這篇文章給大家介紹Android中怎么使用Intent傳輸包含自定義類的ArrayList,內(nèi)容非常詳細(xì),感興趣的小伙伴們可以參考借鑒,希望對(duì)大家能有所幫助。
Serializable
Java的對(duì)象序列化指的是將那些實(shí)現(xiàn)了Serializable接口的對(duì)象轉(zhuǎn)換成一個(gè)字節(jié)序列,并且能在需要的時(shí)候再將這個(gè)字節(jié)序列完全恢復(fù)為之前的對(duì)象。
想實(shí)現(xiàn)對(duì)象的序列化,需要實(shí)現(xiàn)java.io.Serializable接口(注意,這個(gè)接口只是一個(gè)標(biāo)記接口,并沒有具體需要override的方法)。當(dāng)然,你也可以自己實(shí)現(xiàn)對(duì)象的序列化,但是我認(rèn)為既然Java提供了這么一套對(duì)象序列化的機(jī)制,我們最好還是使用官方提供的方法。
Example
創(chuàng)建一個(gè)簡(jiǎn)單對(duì)象,并且實(shí)現(xiàn)Serializable接口
package javastudy; import java.io.Serializable; public class Person implements Serializable { private static final long serialVersionUID = -6470574927973900913L; private String firstName; private String secondName; // example for transinet private transient String noSerializableString; public Person(String firstName, String secondName, String noSerializableString) { super(); this.firstName = firstName; this.secondName = secondName; this.noSerializableString = noSerializableString; } public String getFirstName() { return firstName; } public void setFirstName(String firstName) { this.firstName = firstName; } public String getSecondName() { return secondName; } public void setSecondName(String secondName) { this.secondName = secondName; } public String getNoSerializableString() { if (noSerializableString != null) { return noSerializableString; } else { return ""; } } public void setNoSerializableString(String noSerializableString) { this.noSerializableString = noSerializableString; } public String toString() { return "Person [ first name :" + getFirstName() + ", second name :" + getSecondName() + ", no serializable :" + getNoSerializableString() + "]"; } }
再寫一個(gè)類,用于實(shí)現(xiàn)對(duì)象的序列化和反序列化
package javastudy; import java.io.FileInputStream; import java.io.FileOutputStream; import java.io.IOException; import java.io.ObjectInputStream; import java.io.ObjectOutputStream; public class TestSerializable { public static void main(String[] args) { Person person = new Person("Wang", "Zhengyi", "Genius"); String fileName = "/tmp/person.out"; // save object to file FileOutputStream fos = null; ObjectOutputStream out = null; try { fos = new FileOutputStream(fileName); out = new ObjectOutputStream(fos); out.writeObject(person); out.flush(); } catch (Exception e) { e.printStackTrace(); } finally { if (fos != null) { try { fos.close(); } catch (IOException e) { e.printStackTrace(); } } if (out != null) { try { out.close(); } catch (IOException e) { e.printStackTrace(); } } } // read object from file FileInputStream fin = null; ObjectInputStream in = null; try { fin = new FileInputStream(fileName); in = new ObjectInputStream(fin); Person p = (Person) in.readObject(); System.out.println(p); } catch (Exception e) { e.printStackTrace(); } finally { if (fin != null) { try { fin.close(); } catch (IOException e) { e.printStackTrace(); } } if (in != null) { try { in.close(); } catch (IOException e) { e.printStackTrace(); } } } } }
Intent傳輸包含自定義類的ArrayList
之所以之前介紹了Serializable,是因?yàn)檫@是實(shí)現(xiàn)Intent傳輸?shù)那疤?,ArrayList包含的自定義類必須實(shí)現(xiàn)Serializable接口才能通過putSerializable()
方法被傳遞。
還是用上面的Person類作為自定義的類,則第一個(gè)傳遞ArrayList的Activity關(guān)鍵代碼如下:
// Intent Creation and Initialization Intent passIntent = new Intent(); passIntent.setClass(MainActivity.this, SecondaryActivity.class); // Create custom class Object Person p1 = new Person("Wang", "Zhengyi", "first"); Person p2 = new Person("Chen", "Shan", "second"); // Create Array List of custom Class and add the Created object ArrayList<Person> aListClass = new ArrayList<Person>(); aListClass.add(p1); aListClass.add(p2); // Create a Bundle and Put Bundle in to it Bundle bundleObject = new Bundle(); bundleObject.putSerializable("key", aListClass); // Put Bundle in to Intent and call start Activity passIntent.putExtras(bundleObject); startActivity(passIntent);
第二個(gè)接收ArrayList的Activity關(guān)鍵代碼如下:
try{ // Get the Bundle Object Bundle bundleObject = getIntent().getExtras(); // Get ArrayList Bundle ArrayList<Person> classObject = (ArrayList<Person>) bundleObject.getSerializable("key"); Retrieve Objects from Bundle for(int index = 0; index < classObject.size(); index++){ Person person = classObject.get(index); Toast.makeText(getApplicationContext(), person, Toast.LENGTH_SHORT).show(); } } catch(Exception e){ e.printStackTrace(); }
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