3. Introduction
What is Data Binding?
- Data binding binds a data model object to a UI elements
- Announced at Google I/O 2015
Model Binding View
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4. Introduction
Why do we need it?
- Remove unnecessary code ( add…Listener, findViewById, setText)
- Aid Memory Management
- Value code quality
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5. Introduction
Why do we need it?
- Remove unnecessary code ( add..Listener, findViewById, setText)
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@Override
public void onBindViewHolder(MyViewHolder holder, final int position) {
holder.getmItemBinding().setUser(mUserList.get(position));
holder.getmItemBinding().executePendingBindings();
}
@Override
public void onBindViewHolder(MyViewHolder holder, final int position) {
holder.name.setText(..);
holder.age.setText(..);
...
}
N
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7. Using
What do we need?
- Minimum API-level 7 (2.1)
- Android Studio 1.3.0 or higher
- Add library in root build.gradle
- Apply plugin in build.gradle app
dependencies {
..
classpath "com.android.databinding:dataBinder:1.0-rc1"
}
apply plugin: 'com.android.databinding'
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8. Using
How do we use?
- Preparing the Model
- Preparing the Layout
- Connect Model and Layout in your activity
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9. Using
How do we use?
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User.java MainActivity.java
ExampleLayoutBinding
Handler.java
ExampleLayoutBinding.java
public void setHandler(Handler handler);
public void setUser(User user);
…….
example_layout.xml
handler
user
10. Using
How do we use?
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public class User extends BaseObservable{
public String name;
public int age;
//Setter and Getter
}
<layout xmlns:android="http://schemas.android.com/apk/res/android">
<data>
<variable name="user" type="com.dmi.bindingview.User"/>
</data>
<RelativeLayout
......
<TextView
......
android:text="@{user.name}"/>
</RelativeLayout>
</layout>
private ActivityMainBinding mBinding;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
mBinding = DataBindingUtil.setContentView(this, R.layout.activity_main);
mBinding.setUser(mUser);
}
}
User.java
activity_main.xml
MainActivity.class
12. Features
More Features
- Imports Classes
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..
<layout
..
<data>
<import type="android.view.View"/>
<variable name="user" type="com.dmi.bindingview.User"/>
</data>
<LinearLayout
.. >
<TextView
..
android:visibility="@{user.age>20 ? View.VISIBLE : View.GONE}"/>
</LinearLayout>
</layout>
13. Features
More Features
- Supporting Resources
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android:text="@{@string/nameFormat(firstName, lastName)}"
android:text="@{@plurals/banana(bananaCount)}"
android:padding="@{@dimen/largePadding}"
android:textColor="@{@color/red}"
14. Features
More Features
- Expression Languages
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• Mathematical + - / * %
• String concatenation +
• Logical && ||
• Binary & | ^
• Unary + - ! ~
• Shift >> >>> <<
• Comparison == > < >= <=
• instanceof
• Grouping ()
• Literals - character, String, numeric, null
• Cast
• Method calls
• Field access
• Array access []
• Ternary operator ?:
It is like Java expressions
15. Problems
Current Problems
- IDE-Support currently poor
* Error indicated, but it compiles and works
* No code completion in layout
- API not stable, it is in beta.
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