android - Change TextView text

Question

I'm trying to change my TextView text from the code.

This is what my xml looks like:

XML:
<TextView
    android:id="@+id/textView1"
    android:layout_width="fill_parent"
    android:layout_height="wrap_content"
    android:gravity="center_vertical|center_horizontal" />

And the code:

TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");
setContentView(tv1);

I'm getting an error on my device and the application stops. I tried to show a TextView (not connected to an XML TextView) and it worked.

Answer 1

Your approach is incorrect. I think it will be Null Pointer Exception (next time post log cat)

You need to specify the layout you are using first, before finding views.

Java:

// Specify the layout you are using.
setContentView(R.layout.yourlayout);

// Load and use views afterwards
TextView tv1 = (TextView)findViewById(R.id.textView1);
tv1.setText("Hello");

Kotlin:

// Specify the layout you are using.
setContentView(R.layout.yourlayout)

// Load and use views afterwards
val tv1: TextView = findViewById(R.id.textView1)
tv1.text = "Hello"

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