如何在ConstraintLayout中通过代码复制隐藏控件的布局属性

Absolutely! You can replicate the XML changes you made entirely in code using Android's ConstraintSet API, which lets you modify ConstraintLayout constraints dynamically. Here's exactly how to do it:

Step-by-Step Implementation #

First, add an ID to your ConstraintLayout (you didn’t include one in your original XML—add android:id="@+id/main_constraint_layout" to the ConstraintLayout tag), then get references to your views and adjust constraints:

Kotlin Code

// Get references to your views
val constraintLayout = findViewById<ConstraintLayout>(R.id.main_constraint_layout)
val someTitle = findViewById<TextView>(R.id.some_title)
val textView1 = findViewById<TextView>(R.id.textView1)
val textView2 = findViewById<TextView>(R.id.textView2)

// Create a ConstraintSet and clone the current layout constraints
val constraintSet = ConstraintSet()
constraintSet.clone(constraintLayout)

// 1. Hide textView1
constraintSet.setVisibility(textView1.id, View.GONE)
textView1.visibility = View.GONE // Sync the view's visibility directly

// 2. Copy textView1's positioning constraints to textView2
// Align start to parent start with matching margin
constraintSet.connect(
    textView2.id, ConstraintSet.START,
    ConstraintSet.PARENT_ID, ConstraintSet.START,
    16
)
// Align top to someTitle's bottom with matching margin
constraintSet.connect(
    textView2.id, ConstraintSet.TOP,
    someTitle.id, ConstraintSet.BOTTOM,
    8
)
// Align bottom to parent bottom with matching margin
constraintSet.connect(
    textView2.id, ConstraintSet.BOTTOM,
    ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM,
    20
)
// Clear textView2's old end constraint (previously tied to parent end)
constraintSet.clear(textView2.id, ConstraintSet.END)

// 3. Update someTitle's bottom constraint to point to textView2 instead of textView1
constraintSet.connect(
    someTitle.id, ConstraintSet.BOTTOM,
    textView2.id, ConstraintSet.TOP,
    8
)

// 4. Apply textView1's additional layout properties to textView2
constraintSet.setHorizontalBias(textView2.id, 0f) // Match horizontal bias
constraintSet.setConstrainedWidth(textView2.id, true) // Enable constrained width
constraintSet.setWidth(textView2.id, ConstraintSet.WRAP_CONTENT) // Change width from 0dp to wrap_content

// Update view-specific attributes (not managed by ConstraintSet)
textView2.apply {
    setPadding(0, 0, 0, 0) // Remove original top padding
    maxLines = 1
    layoutParams = (layoutParams as ConstraintLayout.LayoutParams).apply {
        marginEnd = 8 // Match textView1's end margin
        maxWidth = resources.getDimensionPixelSize(R.dimen.your_88dp) // Keep maxWidth if needed
    }
}

// 5. Apply the updated constraints to the layout
constraintSet.applyTo(constraintLayout)

Java Code

// Get references to your views
ConstraintLayout constraintLayout = findViewById(R.id.main_constraint_layout);
TextView someTitle = findViewById(R.id.some_title);
TextView textView1 = findViewById(R.id.textView1);
TextView textView2 = findViewById(R.id.textView2);

// Create a ConstraintSet and clone current constraints
ConstraintSet constraintSet = new ConstraintSet();
constraintSet.clone(constraintLayout);

// 1. Hide textView1
constraintSet.setVisibility(textView1.getId(), View.GONE);
textView1.setVisibility(View.GONE);

// 2. Copy textView1's positioning constraints to textView2
constraintSet.connect(
    textView2.getId(), ConstraintSet.START,
    ConstraintSet.PARENT_ID, ConstraintSet.START,
    16
);
constraintSet.connect(
    textView2.getId(), ConstraintSet.TOP,
    someTitle.getId(), ConstraintSet.BOTTOM,
    8
);
constraintSet.connect(
    textView2.getId(), ConstraintSet.BOTTOM,
    ConstraintSet.PARENT_ID, ConstraintSet.BOTTOM,
    20
);
constraintSet.clear(textView2.getId(), ConstraintSet.END);

// 3. Update someTitle's bottom constraint
constraintSet.connect(
    someTitle.getId(), ConstraintSet.BOTTOM,
    textView2.getId(), ConstraintSet.TOP,
    8
);

// 4. Apply additional layout properties
constraintSet.setHorizontalBias(textView2.getId(), 0f);
constraintSet.setConstrainedWidth(textView2.getId(), true);
constraintSet.setWidth(textView2.getId(), ConstraintSet.WRAP_CONTENT);

// Update view-specific attributes
textView2.setPadding(0, 0, 0, 0);
textView2.setMaxLines(1);
ConstraintLayout.LayoutParams params = (ConstraintLayout.LayoutParams) textView2.getLayoutParams();
params.setMarginEnd(8);
params.maxWidth = getResources().getDimensionPixelSize(R.dimen.your_88dp);
textView2.setLayoutParams(params);

// 5. Apply constraints to the layout
constraintSet.applyTo(constraintLayout);

Key Notes #

• Make sure to replicate all margins, biases, and layout flags (like constrainedWidth) to match your modified XML exactly.
• Attributes like maxLines and padding are view-specific, so you’ll need to update them directly on the TextView instead of via ConstraintSet.

内容的提问来源于stack exchange，提问作者K.Os