使用Java的简单Android Studio TextView代码

Question

I am trying to create a TextView in Android Studio using the code on their reference (I already know I can use XML but I am trying to learn java). My code doesn't work and I can't figure out why. I look just like the code on the reference. I am trying to figure out how to use the Android reference guide to code in Android Studio. Any tips and tricks for using the reference guide are appreciated too.

Note: Please no comments saying I need to buy a java book, take a java class, etc because I am already doing that.

The reference I am referring to ( http://developer.android.com/reference/android/widget/TextView.html# )

    //(class) Adds TextView
public class TextView extends MainActivity{
    CharSequence myText = "Marsha Jackson - (555) 555-5555 - marsha.jackson@email.com - www.jkl.com";

    //(method) Sets width for the textview
    public void setWidth (int pixels){
        int = 100;
    }

    //(method) Sets the height of the TextView
    public void setHeight (int pixels){
        int = 500;
    }
    //(method) Sets the size of the text
    public void setTextSize (float size){
        float = 40;

    }

    //Sets the typeface fo the font
    public void setTypeface (Typeface tf) {
        Typeface Arial;
    }
    //(method) Sets the text color
    public void setTextColor (ColorStateList colors){
        ColorStateList Red;
    }

    //(method) Sets the colors for links
    public final void setLinkTextColor (int color) {
        int Yellow;
    }

    //(method)Sets highlighted text color
    public void setHighlightColor (int color){
        int Green;
    }

    //(method) Sets text to be ellipsized
    public void setEllipsize (TextUtils.TruncateAt where){
        Enum END;
    }

    //(method) Sets text
    public final void setText(CharSequence text){
        myText = text;
    }
    //(method)Makes text selectable
    public void setTextIsSelectable (boolean selectable){

    }

    //(method) Return the state of the textIsSelectable flag
    public boolean isTextSelectable(){
        return (setTextIsSelectable);

    }
    //(Method) Lets user select websites, phone numbers, and emails
    public final void setAutoLinkMask (int mask){
        public static final int all{

        }
        //(Field)Filters out numbers that are too short to be phone numbers
        public static final Linkify.MatchFilter sPhoneNumberMatchFilter{

        }
        //(Field)Filters out symbols that can be in phone numbers
        public static final Linkify.TransformFilter sPhoneNumberTransformFilter{

        }
        //(Field) Prevent text after @ sign from becoming a website link
        public static final Linkify.MatchFilter sUrlMatchFilter{

        }
    }

}

Answer 1

if I understand correctly what you're trying to accomplish, is with java code create a TextView in an Android App. If so, you are aproaching it the wrong way. Let me explain:

What you are doing; You are creating an Activity that extends (inherits in Object Oriented Programming lexicon) TextView, and then use TextView methods to change the appearance of the widget. What this means is that you are making the whole app a single TextView Widget and then overloading its methods with your intended changes which is not the way the platform was designed.

What I think you should do; use the Android Studio wizard that creates a blank activity (as shown in http://developer.android.com/training/basics/firstapp/creating-project.html ). Remove the "Hello World!" TextView from activity_main.xml. In MainActivity.java. you can create the TextView and fill it out inside the onCreate method with code like this:

protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    TextView myTextView = new TextView(this);
    myTextView.setText("Marsha Jackson - (555) 555-5555 - marsha.jackson@email.com - www.jkl.com");
    myTextView.setWidth(100);
    myTextView.setHeight(500);
    //you can keep adding code to change myTextView
    setContentView(myTextView);
}

Hope that it helps and sets you in the right direction.

Answer 2

You just handle the textview in java you declare them and use java to set the text and you put textview in your layout to show them to user

For example see :

You have a layout file such as main.xml In that you add TextView

<TextView
    android:id=@+id/text
  />

And in java you do this

 TextView t = (TextView) findViewById(R.id.text);

And set text using

 t.settext("your text")

Edit as promised

You can have a clicklistener on TextView Example :

text2.setOnClickListener(newView.OnClickListener() {    
    public voidonClick(View v) {    
   Toast.makeText(getApplicationContext(),"Text was clicked",    
   Toast.LENGTH_LONG).show();

And there are also some XML attributes to help in formating
For it consider the following:

<TextView

        android:layout_width="wrap_content"

        android:layout_height="wrap_content"

        android:id="@+id/text1"

        android:text="@string/hello_world"

        android:textStyle="bold"

        android:textColor="#ff00ff"

        android:background="#00ff00"

        android:textColorHighlight="#000000"

        android:textIsSelectable="true"/>

You can also set this attributes dynamically also using java

Like this :

Text.settext(" ");
Text.setheight(" ");

And other

Answer 3

They way that you are doing it is unnecessary. These methods are already built into the TextView object. You don't need to rebuild them. This is doubling your work. Just instantiate a TextView object and then call those methods.

// access textview that is in xml layout file
TextView textView = (TextView) findViewById(R.id.textView);
textView.setText("Hello");
textView.setTextHeight(45);
....