Tasker

Tasker Automation

Tasker is a comprehensive automation app for Android that uses a trigger-action model to automate tasks based on contexts (conditions).

Core Concepts

• Profiles: Connects triggers (Contexts) to tasks (Enter Task and optional Exit Task).
• Contexts: Triggers that can be based on State (persistent condition), Event (one-off occurrence), Time, Day, Location, or Application (foreground app).
• Tasks: A named sequence of Actions executed step-by-step.
• Variables: State holders starting with %.
  • Global Variables: Contain at least one capital letter (e.g., %MyGlobal). Persisted and shared across all Profiles and Tasks.
  • Local Variables: All lowercase (e.g., %local_var). Created and used only within the current execution of a Task.

Reference Documentation

Detailed references are partitioned as follows to avoid context bloat:

• Profiles & Contexts: See contexts.md for details on Time, Day, Location, State, and Event contexts.
• Tasks & Actions: See tasks.md for detailed descriptions of Task parameters, Flow Control (If, Else, End If, For, Goto), Widgets, and specific actions.
• Variables & Logic: See variables.md for built-in variables, custom variables, variable formatting, pattern matching, and mathematical expressions.
• Scenes & UI: See scenes.md for UI elements (buttons, sliders, text inputs), scene properties, and element actions.
• Advanced Features: See advanced.md for JavaScriptlets, Java Object creation, Android Intents, Midi control, and Power management.

Tasker Development Workflow

When designing a Tasker automation, follow this workflow:

1. Identify the Trigger: Determine if the trigger is a State (e.g., connected to a specific Wi-Fi) or an Event (e.g., receiving an SMS).
2. Design the Task: List the actions needed. If stateful, decide if you need an Exit Task to revert settings when the state changes.
3. Use Local Variables: Keep intermediate states in local (all-lowercase) variables to prevent global namespace pollution.
4. Error Handling: Use the %err and %errmsg local variables after actions that might fail (e.g., HTTP request, file read) to gracefully handle failures.

Scripting in Tasker

JavaScript / JavaScriptlet Action

You can execute JavaScript within a task. In JavaScriptlets:

• Access local/global Tasker variables directly by name without the % (e.g., local variables as localvar and global as GLOBALVAR).
• Use setLocal('varname', value) to set local variables.
• Use setGlobal('VARNAME', value) to set global variables.
• Example:

  var battery = global('BATT');
  if (battery < 20) {
      setLocal('low_power', 'true');
  }
  

Shell Commands

Run shell commands via the Run Shell action.

• Ensure "Use Root" is checked only if root permissions are required.
• Store output in %stdout and errors in %stderr.

Android Intents

Send broadcast, activity, or service intents using the Send Intent action.

• Action: The intent action (e.g., android.intent.action.VIEW).
• Cat: Category (e.g., Default).
• Data: Data URI (e.g., https://example.com).
• Extra: Key-value extras (e.g., key:value).

Exporting & Importing Configurations

Tasker is highly sensitive to the structure of exported XML configurations.

File Extensions

For Tasker to recognize the XML data during an import, files must end with specific double extensions:

• Projects: .prj.xml
• Profiles: .prf.xml
• Tasks: .tsk.xml
• Scenes: .scn.xml

XML Root Structure

Tasker requires files to start directly with the <TaskerData> root tag. Including standard XML headers (like <?xml version="1.0" encoding="utf-8"?>) or other root wrappers will fail to parse and trigger errors.

Matching Import Actions with UI Elements

Tasker's UI contains isolated import functions. Selecting a file that doesn't match the import context will trigger errors (e.g., "no Project found"):

• Importing a Project: Long-press on the Project/Home tab at the bottom of the screen and choose Import Project.
• Importing a Profile/Task/Scene: Tap the corresponding tab at the top, long-press the tab label, and choose Import.