用Intent传递对象

用Intent传递对象

用Intent传递基本数据类型 字符串 数组等，大家都已经轻车熟路了，但传递参数类型不仅仅于此，我们还可以传递对象作为参数。

传递方式

• Serializable方式：将整个对象序列化并传递。
• Parcelable方式：将完整的对象分解成Intent支持的数据类型，再传递。

Serializable方式

对象实现Serializable接口，Intent调用getSerializableExtra()获取参数。

Parcelable方式

对象实现Parcelable接口，重写describeContents(),wtiteToParcel()，提供一个CREATE常量。

示例代码

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TestPersonSerializable.java

public class TestPersonSerializable implements Serializable {

    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String description() {
        StringBuilder sb = new StringBuilder();
        sb.append(" name : ").append(name).append(" ,");
        sb.append(" age : ").append(age).append("\n");
        return sb.toString();
    }
}

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TestPersonParcelable.java

public class TestPersonParcelable implements Parcelable {

    @Override
    public int describeContents() {
        return 0;
    }

    @Override
    public void writeToParcel(Parcel dest, int flags) {
        // 此处将各个属性调用对应方法全部写出
        dest.writeString(name);
        dest.writeInt(age);
    }

    /**
     * CREATOR常量
     */
    public static final Parcelable.Creator<TestPersonParcelable> CREATOR =
            new Parcelable.Creator<TestPersonParcelable>() {
                @Override
                public TestPersonParcelable createFromParcel(Parcel source) {
                    TestPersonParcelable person = new TestPersonParcelable();
                    person.name = source.readString();
                    person.age = source.readInt();
                    return person;
                }

                @Override
                public TestPersonParcelable[] newArray(int size) {
                    return new TestPersonParcelable[size];
                }
            };

    private String name;
    private int age;

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

    public int getAge() {
        return age;
    }

    public void setAge(int age) {
        this.age = age;
    }

    public String description() {
        StringBuilder sb = new StringBuilder();
        sb.append(" name : ").append(name).append(" ,");
        sb.append(" age : ").append(age).append("\n");
        return sb.toString();
    }
}

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activity_intent_object_one.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".chapter13.IntentObjectOneActivity"
    android:orientation="vertical">

    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <Button
                android:id="@+id/btn_ioo_serializable"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Serializable 实现" />
            <Button
                android:id="@+id/btn_ioo_parcelable"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="Parcelable 实现" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="反馈回来的数据"/>
            <TextView
                android:id="@+id/tv_ioo_res"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </LinearLayout>
    </ScrollView>

</LinearLayout>

---

IntentObjectOneActivity.java

public class IntentObjectOneActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_intent_object_one);

        Button btn_ioo_serializable = findViewById(R.id.btn_ioo_serializable);
        btn_ioo_serializable.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                TestPersonSerializable person = new TestPersonSerializable();
                person.setName("DJ Serializable");
                person.setAge(80);
                Intent intent = new Intent(
                        BLApplication.getContext(), IntentObjectTwoActivity.class);
                intent.putExtra("person", person);
                intent.putExtra("type", 1);
                startActivity(intent);
            }
        });

        Button btn_ioo_parcelable = findViewById(R.id.btn_ioo_parcelable);
        btn_ioo_parcelable.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {
                TestPersonParcelable person = new TestPersonParcelable();
                person.setName("DJ Parcelable");
                person.setAge(80);
                Intent intent = new Intent(
                        BLApplication.getContext(), IntentObjectTwoActivity.class);
                intent.putExtra("person", person);
                intent.putExtra("type", 2);
                startActivity(intent);
            }
        });
    }
}

---

activity_intent_object_two.xml

<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:app="http://schemas.android.com/apk/res-auto"
    xmlns:tools="http://schemas.android.com/tools"
    android:layout_width="match_parent"
    android:layout_height="match_parent"
    tools:context=".chapter13.IntentObjectTwoActivity"
    android:orientation="vertical">

    <ScrollView xmlns:android="http://schemas.android.com/apk/res/android"
        android:layout_width="match_parent"
        android:layout_height="match_parent"
        android:scrollbars="vertical">

        <LinearLayout
            android:layout_width="match_parent"
            android:layout_height="match_parent"
            android:orientation="vertical">

            <Button
                android:id="@+id/btn_iot"
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="返回" />

            <TextView
                android:layout_width="match_parent"
                android:layout_height="wrap_content"
                android:text="传递过回的Object数据"/>
            <TextView
                android:id="@+id/tv_iot_res"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />

        </LinearLayout>
    </ScrollView>

</LinearLayout>

---

IntentObjectTwoActivity.java

public class IntentObjectTwoActivity extends AppCompatActivity {

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_intent_object_two);

        Button btn_iot = findViewById(R.id.btn_iot);
        btn_iot.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View v) {

            }
        });

        TextView tv_iot_res = findViewById(R.id.tv_iot_res);
        int type = getIntent().getIntExtra("type", 0);
        if (type == 1) {
            TestPersonSerializable person = (TestPersonSerializable) getIntent()
                    .getSerializableExtra("person");
            tv_iot_res.setText(person.description());
        } else if (type == 2) {
            TestPersonParcelable person = (TestPersonParcelable) getIntent()
                    .getParcelableExtra("person");
            tv_iot_res.setText(person.description());
        }

    }
}

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